Effect of Coconut Water Compared to Oral Electrolytes on Hydration Status in Adolescents Who Perform Physical Exercise: Randomized Clinical Trial, Double-blind
Phase: PHASE4
Conditions: Sports Nutrition
Sponsor: Universidad de Colima

1 
 
 
School of Medicine 
Effect of coconut water compared with oral electrolytes on hydration status 
in adolescents who perform physical exercise of aerobic competition. 
Randomized, double-blind controlled clinical trial. 
TO OBTAIN THE DEGREE OF: 
MASTER IN MEDICAL SCIENCES 
 
PRESENTS: 
LN. Alexis Adan Lopez Maria 
 
ADVISORS: 
D in C Carmen Alicia Sánchez Ramírez 
D in C Fabian Rojas Larios 
CO-ADVISOR: 
D on C Yunue Flores Ruelas 
DATE: COLIMA, COL. JANUARY 15th, 2025 (NCT: NCT05562401) 

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INDEX 
1 
ABSTRACT: .............................................................................................................. 7 
2 
INTRODUCTION ..................................................................................................... 7 
3 
THEORETICAL FRAMEWORK ........................................................................... 8 
3.1 
Water ........................................................................................................................ 8 
3.1.1 
Composition and structure. ............................................................................... 8 
3.1.2 
Functions......................................................................................................... 10 
3.1.3 
Distribution of Total Body Water (TBW) ...................................................... 11 
3.1.4 
Water homeostasis .......................................................................................... 12 
3.1.5 
Thirst mechanism............................................................................................ 13 
3.1.6 
Renin Angiotensin Aldosterone System (RAAS)........................................... 13 
3.2 
Hydration Status..................................................................................................... 14 
3.2.1 
Prevalence of dehydration .............................................................................. 15 
3.2.2 
Classification of dehydration based on the loss of water and sodium. ........... 15 
3.2.3 
Fluid requirements in athletes......................................................................... 17 
3.2.4 
Consequences of dehydration ......................................................................... 18 
3.3 
Physical exercise as an important factor of dehydration........................................ 19 
3.3.1 
Types of physical exercise .............................................................................. 20 
3.3.2 
Exercise intensity ............................................................................................ 20 
3.3.3 
Prevalence of dehydration in athletes ............................................................. 22 
3.4 
Factors that alter hydration status .......................................................................... 22 
3.4.1 
Obesity ............................................................................................................ 22 
3.4.2 
Climate............................................................................................................ 23 
3.4.3 
Feeding Habits ................................................................................................ 24 
3.5 
Diagnostic methods of dehydration ....................................................................... 25 
3.5.1 
Gold standard .................................................................................................. 26 
3.5.2 
Urine Specific Gravity (USG) ........................................................................ 27 
3.5.3 
Total Body Water Loss by bioimpedance (PACT)......................................... 27 
3.5.4 
Total Body Mass Loss (TWBC) ..................................................................... 29 
3.6 
Hydrating drinks .................................................................................................... 30 
3.6.1 
Oral electrolytes .............................................................................................. 31 
3.6.2 
Disadvantages of using industrialized beverages ........................................... 32 
3.6.3 
Coconut water ................................................................................................. 32 

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3.6.4 
Chemical composition of coconut water ........................................................ 33 
3.6.5 
Chemical comparison between oral electrolytes, Coconut water and 
Electrolit® ..................................................................................................................... 35 
4 
BACKGROUND. ..................................................................................................... 36 
5 
PROBLEM STATEMENT ..................................................................................... 39 
6 
JUSTIFICATION .................................................................................................... 40 
6.1 
Research question .................................................................................................. 41 
7 
MATERIAL AND METHODS .............................................................................. 41 
7.1 
Hypothesis.............................................................................................................. 41 
7.1.1 
Work hypothesis ............................................................................................. 41 
7.1.2 
Null hypothesis ............................................................................................... 41 
7.1.3 
Alternate hypothesis ....................................................................................... 42 
7.2 
Objectives............................................................................................................... 42 
7.2.1 
General objective ............................................................................................ 42 
7.2.2 
Specific objectives .......................................................................................... 42 
7.3 
Trial design ............................................................................................................ 42 
7.3.1 
Study universe ................................................................................................ 43 
7.3.2 
Inclusion criteria ............................................................................................. 43 
7.3.3 
Exclusion criteria ............................................................................................ 44 
7.3.4 
Elimination criteria ......................................................................................... 44 
7.4 
Operationalization of variables .............................................................................. 44 
7.4.1 
Independent Variable: Hydrating Drinks........................................................ 44 
7.4.2 
Dependent variable: Hydration status............................................................. 44 
7.4.3 
Variable box.................................................................................................... 46 
7.5 
Sample size ............................................................................................................ 47 
7.6 
Randomization ....................................................................................................... 47 
7.7 
Masking or blinding ............................................................................................... 48 
7.8 
Interventions........................................................................................................... 48 
7.8.1 
Flowchart ........................................................................................................ 49 
7.8.2 
Execution protocol taking into account the epidemiological situation of 
CoVid-19 ....................................................................................................................... 49 
7.8.3 
Hydrating drinks ............................................................................................. 52 
7.8.4 
Meal plan ........................................................................................................ 53 

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7.9 
Methods and statistical analysis ............................................................................. 53 
8 
ETHICAL ASPECTS .............................................................................................. 54 
9 
RESULTS ................................................................................................................. 55 
9.1 
Description of the subjects prior to the exercise sessions ...................................... 56 
9.2 
RR, RRR and NNT tests ........................................................................................ 58 
9.3 
Frequency of hydration status per exercise session ............................................... 58 
9.4 
Comparison between groups using Chi square test ............................................... 59 
9.5 
Intragroup comparison in the different sessions .................................................... 59 
10 
DISCUSSION ........................................................................................................... 60 
10.1 Limitations ............................................................................................................. 61 
11 
CONCLUSION ........................................................................................................ 62 
12 
PERSPECTIVES ..................................................................................................... 62 
13 
REFERENCES ........................................................................................................ 62 
14 
ANNEXES ................................................................................................................ 68 
14.1.1 
Annex 1: Urine collection technique, conservation and analysis. .................. 68 
14.1.2 
Annex 2: Aspects to be evaluated to measure physical health as an inclusion 
criterion. 68 
14.1.3 
Annex 3: Criteria for measuring mental health in sports performance. ......... 69 
14.1.4 
Annex 4: Health protocol to be followed by the educational institution. ....... 69 
14.1.5 
Annex 5: Personal information collection sheet for each subject................... 70 
14.1.6 
Annex 6: CPRD Test ...................................................................................... 70 
14.1.7 
Annex 7: Correct weighing according to ISAK guidelines ............................ 78 
14.1.8 
Annex 8: Study authorization letter issued by the ISFPG institution. ............ 78 
14.1.9 
Annex 9: Request letter to carry out research within the ISFPG.................... 79 
14.1.10 
Annex 10: Informed consent letter for father, mother, or guardian. ........... 80 
14.1.11 
Annex 11: Informed assent letter for the minor. ......................................... 81 
14.1.12 
Annex 12: Letter approved by the Research Ethics Committee of the State 
Institute of Cancerology in Spanish and English. ......................................................... 82 
14.2 Viability ................................................................................................................. 84 
14.2.1 
Feasibility ....................................................................................................... 84 
14.2.2 
Human Resources ........................................................................................... 84 
14.2.3 
Financial resources ......................................................................................... 84 
14.2.4 
Financing ........................................................................................................ 84 

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14.3 Schedule of activities ............................................................................................. 85 
14.3.1 
CONSORT check list ..................................................................................... 86 
 
 
INDEX OF FIGURES. 
Figure 1. Atomic structure of water............................................................................................. 9 
Figure 2. Electrostatic relationship of water................................................................................. 9 
Figure 3. Mechanism of RAAS................................................................................................. 14 
Figure 4. Graphical derivation of the phase angle and its relationship with resistance ®, reactance 
(Xc) and impedance (Z). .......................................................................................................... 28 
Figure 5. Parallel design of an RCT. ......................................................................................... 43 
Figure 6. Randomization using the balanced block method......................................................... 48 
Figure 7. Flowchart of the progress of the phases of a parallel RCT of two groups. ...................... 49 
 
TABLE INDEX. 
 
Table1. Percentage of water contained in the different tissues of the human body. ....................... 10 
Table3. Net body fluid balance and your average volume (mL) of water gain or water loss. ......... 12 
Table4.Classification of AD based on clinical signs and symptoms. ............................................ 15 
Table5. AD classification with respect to Na+ and water loss and its most common etiologies...... 16 
Table6. Physiological responses of the organism to dehydration. ................................................ 18 
Table7. Classification of PA and its intensity with respect to the METs used. .............................. 21 
Table8. Intensity classification according to the METs used in each sport per 1 hour of PA(30).... 21 
Table9. Area of the state of Colima by type of climate and annual temperature in °C. .................. 23 
Table10. Cut-off points for euhydration in the different indicators. ............................................. 26 
Table12. Hydration status with respect to ACT loss by bioimpedance. ........................................ 29 
Table13. State of hydration with respect to the percentage of weight loss (%PP).......................... 29 
Table14. Classification of hydrating drinks ............................................................................... 30 
Table16. Chemical comparison between powdered oral electrolytes, Coconut Water and Electrolit® 
per 100 ml............................................................................................................................... 35 
Table17. Variable box ............................................................................................................. 46 
Table18. Nutritional composition of the sports drink that will be used in the project (Electrolit®). 52 
Table19. Description of the study population............................................................................. 55 
Table22. Comparison of pre and post hydration indicators in the CW group ................................ 57 
Table23. Comparison of pre and post hydration indicators in the OE group ................................. 57 
Table24. General cross table of the state of hydration with respect to the assigned treatment. ....... 57 
Table25. Estimation of RA, RR, RAR, NNT and RRR............................................................... 58 
Table26. General table of sessions regarding treatment and hydration status................................ 58 
Table27. Chi square broken down by sessions ........................................................................... 59 
 
 

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ABBREVIATIONS: 
 
CW: Coconut water. 
TBW: Total Body Water. 
ADH: Antidiuretic hormone. 
PA: Physical activity 
HD: Hydrating drinks. 
EBI: Electrical bioimpedance. 
Gl: Glycemic load. 
CRPD: Psychological Characteristics related to Sports Performance. 
PE: Physical exercise. 
ENSANUT: National Survey of Health and Nutrition. 
OE: Oral Electrolytes 
USG: Urine Specific Gravity. 
USGf: Final Urine Specific Gravity. 
USGi: Initial Urine Specific Gravity. 
HCO: Carbohydrates. 
IG: Glycemic index. 
BMI: Body Mass Index. 
ISFPG: Fray Pedro de Gante Salesian Institute. 
LEC: extracellular fluid 
LIC: intracellular fluid 
BM: Body mass 
UCol: Urine color. 
WHO: World Health Organization 
UOsm: Urine osmolality. 
Wf:  final weight 
Wi: initial weight 
WL: Weight loss 
TBWL: Total body water loss 
OW: Overweight 
RAAS: Renin Angiotensin Aldosterone System. 

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1 
ABSTRACT: 
Introduction: Dehydration is a very common problem that is often not identified. The 
pediatric population is more susceptible to dehydration due to its physiological 
characteristics. Proper hydration is crucial for health since any degree of dehydration causes 
a reduction in physical and mental work capacity, hence the importance of preventing it by 
considering the type of drink. There are multiple beverage options, including industrial oral 
electrolytes (OE), on the other hand, coconut water (CW) has been studied as a natural 
alternative beverage with characteristics that can help maintain a state of euhydration. 
Purpose: To determine if CW has a greater effect on hydration status than EO in adolescents 
who perform physical exercise. Materials and methods: RCT, double blind. 34 subjects 
aged 13.02 ± 1.08 years were selected, assigned to treatment with either OE (Electrolit®) or 
CW. They received a weekly physical exercise session (4 weeks). Hydration was 
personalized (ml x kilograms of weight) and hydration was evaluated by Urine Specific 
Gravity (USG), Total Body Water (TBW) by bioimpedance and changes in body mass. 
Results: There were no significant differences in hydration in the first 3 exercise sessions 
(p>0.05), however, in the last session there was a significant difference between treatments 
(p=0.003). Conclusion: CW and OE have the same effect on hydration levels in adolescents 
who perform physical exercise, except for the last session where the effect was beneficial 
with CW compared with OE. 
 
2 
INTRODUCTION 
Sports nutrition is a specialized branch of nutrition, which is responsible for taking care of 
nutrition and hydration before, during and after exercise or competition in athletes. Physical 
activity has been related to the prevention of chronic non-communicable diseases thanks to 
its protective health benefits, however, dehydration is a very common problem that occurs in 
the population that performs physical activity, exercise, or sports. Hydration status is difficult 
to measure because it is a dynamic process; that is to say, it is constantly modified and varies 
in each individual so, to measure the state of hydration, what is actually examined is the 
variation instead of the absolute degree of hydration through different methods such as 
plasma osmolality, isotopic dilution, bioimpedance, urine specific gravity, urine color, and 

8 
 
changes in body mass. Many times, it is not possible to identify dehydration because there 
are no signs or symptoms in its first stages and when the thirst mechanism is activated there 
is already a degree of dehydration. 
The pediatric population is more susceptible to dehydration due to its physiological 
characteristics and its low capacity for thermoregulation. Proper hydration is crucial for 
health since any degree of dehydration causes a reduction in physical and mental work 
capacity, hence the importance of preventing it by considering the type of drink, quantity, 
and administration times. There are currently multiple beverage options, including industrial 
oral electrolytes, which have been shown in different studies to induce weight gain due to the 
high amounts of added sugar they contain and tooth wear due to acidic pH (1,2). On the other 
hand, Coconut Water (AC) is a natural alternative drink with chemical characteristics that 
can favor an optimal state of hydration in addition to being a fruit that is easily found in the 
state of Colima. 
 
3 
THEORETICAL FRAMEWORK 
 
3.1 
Water 
The common name applied to the liquid state of the compound of hydrogen and oxygen: 
H2O(3). Water is the most abundant component of the human body, by itself the organism is 
unable to produce it in sufficient quantities to cover its needs, for which it must be considered 
as an essential nutrient for life.(4). 
 
3.1.1 Composition and structure. 
It is made up of two hydrogen atoms covalently bonded to one oxygen atom.(4). The oxygen 
atom and the two hydrogen atoms occupy the vertices of an isosceles triangle (Figure 1). The 
electrons of the molecule are arranged in such a way that accumulations of positive and 
negative charges are produced alternately arranged in space. This separation of charges 
causes the molecule to form an electric dipole.(3). 
 

9 
 
 
Figure1. Atomic structure of water. 
Source: Aranalde, G (2015). Kidney Physiology. 
 
This bond profoundly affects the physicochemical properties of water and is the basis of a 
series of essential functions for life. In fact, biological structures such as proteins and 
phospholipid membranes maintain their shape and structure through an electrostatic 
relationship with the water that surrounds them ( Figure 2)(3). 
 
 
 
Figure two. Electrostatic relationship of water. 
Source: Aranalde, G (2015). Kidney Physiology. 
 

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3.1.2 Functions 
It is the main indispensable constituent of all cells, animal and plant, and life cannot exist in 
its absence even for a limited period.(3). Water fulfills many functions inside and outside our 
body, among the main ones is that it serves as a reactive and transport medium. It is the main 
cellular and blood component that transports nutrients, hormones and oxygen throughout the 
body, in addition to facilitating waste substances as well as giving structure to the body 
through the rigidity it provides to body tissues.(5). Water has thermal properties, so in 
physically active people it helps to maintain a constant body temperature balance, especially 
during prolonged exercise in a hot and humid environment.(6). Its high specific heat makes 
it an exceptional shock absorber and thermoregulator, thus maintaining constant body 
temperature. On the other hand, its high value of vaporization heat allows large amounts of 
heat to be eliminated through sweat, avoiding problems in organic systems and preserving us 
from “heat strokes”(7)In addition, studies have linked adequate water consumption with 
better quality eating plans, better health habits and a lower risk of developing chronic 
diseases(8). Water is found in all tissues in different percentages (table 1) and is essential for 
life, for this reason, human beings can live for several weeks without eating any food, but 
with water deprivation they could only survive a few days. The loss of just 10% of body 
water can already cause very serious disorders in the individual and the loss of 20% of water 
can cause death(9). 
 
Table1. Percentage of water contained in the different tissues of the human body. 
Body Tissue 
Water (%) 
Water (L) 
Kidney 
83 
0.25 
Lung 
80 
0.40 
Blood 
76 
4.65 
Brain 
75 
1 
Muscle 
76 
22.10 
Skin 
72 
10 
Bone 
22 
2.45 
fat cells 
10 
0.70 

11 
 
Source: Gonzalez MJ (2006). Water. 
 
3.1.3 Distribution of Total Body Water (TBW) 
The water content is variable between organisms of the same species. Young tissues have a 
greater amount of water, this is lost as they age. Table 2 shows the variations of the 
percentage of body water with respect to the total body mass according to age and sex.(3). 
Table two. Evolution of the percentage of ACT according to age and sex. 
Population 
ACT (% body weight) 
women 
ACT (% body weight) 
males 
>50 years 
47 (39-57) 
56 (47-67) 
19-50 years 
50 (41-60) 
59 (39-57) 
12-18 years 
56 (49-63) 
59 (52-66) 
1-12 years 
60 (49-75) 
60 (49-75) 
6 months-1 year 
60 (57-64) 
60 (57-64) 
newborn-6 months 
47 (39-57) 
47 (39-57) 
Source: Aranalde, G (2015). Kidney Physiology. 
In parentheses is the normal body water percentage range for age and sex. 
 
On average, 63% of the weight in an adult man is water, while in women, water is equivalent 
to between 50 and 55% of the total body mass because they have a higher proportion of body 
fat. In newborns, water occupies up to 75% of the weight(10). In adolescence they decrease 
slowly, being more pronounced in women, who after reaching puberty present 2%-10% less 
ACT(eleven). There are two large compartments into which the distribution of water in the 
body is divided and which differ in their volume and composition, they are called intracellular 
fluid (ICF) and extracellular fluid (ECF).(3). Approximately 65% of the water content in 
organisms is found in the cells and 35% in the extracellular space.(12). This last compartment 
is divided into interstitial fluid and plasma (aqueous content of the blood), which are 
equivalent to 75% and 25%, respectively, of the ECF. 
 

12 
 
3.1.4 Water homeostasis 
Homeostasis is the exact regulation of the volume and composition of fluids in the body. 
Water balance is essential because small changes in water balance can cause major changes 
in metabolic processes. The human body is in homeostasis when it contains optimal 
concentrations of gases, nutrients, ions, and water. When this homeostasis is altered, it can 
cause health effects.(3.13). The daily water balance depends on the net difference between 
the gain and loss of water. Water gain comes mainly from 3 components: a) the water 
ingested through the thirst mechanism, b) the water contained in food and c) the water 
generated from metabolism, this last component provides very little water to the body (500 
ml/day), so adequate daily water intake is important to maintain the body in homeostasis(5). 
On the other hand, body water losses have 4 main routes: a) insensible water losses that 
include breathing and evaporation through the skin, b) loss through sweat, c) losses from the 
digestive tract or feces and d.) loss through urine giving a water balance as shown in table 
3(3). 
 
Table2. Net body fluid balance and your average volume (mL) of water gain or water loss. 
Source 
Volume (ml) 
Profits 
• Oral intake 
2000 
• from metabolism 
500 
Total 
2500 
Losses 
• Insensible skin losses 
400 
• Insensible respiratory tract losses 
400 
• sweat losses 
100 
• Fecal losses 
100 
• urine losses 
1500 
Total 
2500 
Source: Aranalde, G (2015). Kidney Physiology. 

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3.1.5 Thirst mechanism 
The human body has developed a precise control system to maintain water balance through 
physiological adaptations, such as decreasing water through excretion through urine or 
increasing it through mechanisms that regulate thirst.(4.5). Thirst is stimulated when cell 
volume or extracellular space decreases. This mechanism is activated by decreasing the 
volume of water in the body causing plasmatic hyperosmolality, this is compensated by the 
outflow of water from the cells due to the osmotic gradient. Small changes in plasma 
osmolality, such as a 1% or 5% decrease in plasma fluid, stimulate secretion of antidiuretic 
hormone (ADH)(5), the osmoreceptors of the pituitary cells detect these changes as well as 
other similar receptors, in this way, two relatively separate mechanisms are activated, one 
that activates thirst and the other that prevents the escape of renal fluid through the Renin 
Angiotensin Aldosterone System ( RAAS). These mechanisms can compensate each other 
when one of the two fails.(9). 
The hypothalamus and adjacent preoptic regions play an essential role in the mechanisms of 
thirst, which is a sensation that occurs when there is a change in the internal environment that 
leads to cellular hypohydration (dehydration), thus thirst; appears when it is already too late, 
because there is already a degree of dehydration which is normally reached when there is a 
loss between 1-2% of the loss of body weight(12), however, there is an anticipation 
mechanism regarding stopping dehydration, where the water is still in the stomach and from 
there and even from the tongue the rehydration signal is sent to the brain, anticipating blood 
dilution by 10 to 20 min. If there is a thermal overheating, sweating immediately begins(9). 
 
3.1.6 Renin Angiotensin Aldosterone System (RAAS) 
The Renin-Angiotensin-Aldosterone System (RAAS) is a proteolytic cascade connected to a 
signal transduction system, establishing it as one of the most important elements involved in 
the regulation of blood pressure as well as the hydro-electrolytic balance of a human 
being(14).When there is a decrease in plasma volume, the renal baroreceptors sensitive to 
pressure changes activate the RAAS, increasing renin secretion, which will act on 
angiotensinogen by splitting this decapeptide from the liver to form Angiotensin I (AG I), 

14 
 
since obtained AG I, is proteolytically converted into angiotensin II (AG II) by Angiotensin 
Converting Enzyme (ACE), mainly at the pulmonary level. However, it is now known that 
many tissues, including blood vessels, kidney, heart, and brain, are also capable of locally 
generating AG II via non-ACE-dependent pathways. AG II acts through at least two classes 
of receptors, the AT-1 and AT-2 receptors. Once the AT-1 receptor is stimulated by AG II, 
expressed mainly in the adrenal cortex,(9.15)(Figure 3). 
 
Figure2. RAAS mechanism. 
Source: Contra, HS (2008). The renin-angiotensin-aldosterone system and its functional role beyond blood 
pressure control. 
 
3.2 
Hydration Status 
The body's water remains constant in its levels in the healthy individual, however it does not 
mean that it is a static system, on the contrary, there is a constant dynamic state where there 
are mechanisms responsible for its internal and external regulation, between the individual 
and his environment, and on the other hand between the various fluid compartments of the 
body(3). The state of optimal water balance is called the state of euhydration in the English 
literature, which is defined as the normal storage and distribution of water in the body in total 
percentages inside and outside the cells to meet the physiological demands of the organism. 
according to their age, physical activity and health status, which were previously written in 

15 
 
the distribution section of the ACT(16). On the other hand, acute dehydration (AD) is defined 
as the clinical state following the loss of water and solutes(17). It is an acute process in which 
water losses are equated to sudden weight loss(18). 
 
3.2.1 Prevalence of dehydration 
The general population, athletes or non-athletes and of different age groups, come to suffer 
dehydration without presenting signs or symptoms and therefore without being aware of it, 
which is why its incidence or prevalence is difficult to determine.(2.10). According to 
Arredondo et al, 2017, it was shown that in countries with dry or hot climates, 70% of 
children were found to be in a state of chronic dehydration with levels of dehydration of at 
least 2% with a significant deterioration of mental functions. (arithmetic ability, motor-visual 
tracking and short-term memory)(4). 
 
3.2.2 Classification of dehydration based on the loss of water and sodium. 
The classification of dehydration is based on the loss of water and electrolytes (mainly 
sodium and potassium) or by weight loss and its clinical signs as shown in Table 4.(18). 
 
 
Table3.Classification of AD based on clinical signs and symptoms. 
Signs and symptoms 
mild AD 
moderate AD 
severe AD 
Awareness 
normal/alert 
irritable/restless 
clouded 
Eyes 
normal 
sunken 
Very sunken/dry 
Tears 
presents 
Missing 
Missing 
mouth/tongue 
pasty 
dry 
Very dry 
Thirst 
regular baby 
Thirsty 
unable to drink 
Skin 
negative fold 
positive fold 
very positive fold 
Weight loss 
<5% 
5-10% 
>10% 
Fontanelle 
Normal 
depressed 
depressed 

16 
 
Tachypnea 
No 
Mild 
moderate 
Blood pressure 
Normal 
Decline 
hypotension/shock 
Increased pulse 
No 
Mild 
rapid and weak pulse 
skin perfusion 
Normal 
cold 
Acrocyanosis 
urine flow 
normal/poor 
Oliguria 
Oliguria/anuria 
Urinary density 
>1,020 
>1,030 
>1,035 
blood pH 
7.30-7.40 
7.10-7.30 
<7.10 
Source: Trevino, SJ (2006). Acute dehydration. Rehydration. 
Based on serum sodium levels, dehydration is classified as: 
• Hypotonic: Hypotonic dehydration occurs when sodium is less than 130 mEq/L, 
indicating that fluid loss is less than electrolyte loss. 
• Isotonic: plasma sodium ranges between 130-150 mEq/L, deducing that the loss of 
water and electrolytes is the same or similar. 
• Hypertonic: sodium is greater than 150 mEq/L and the loss is mostly water. 
There are several important electrolytes in acid-base regulation and hydration maintenance, 
however, sodium and potassium are the ones that are most involved in the state of hydration. 
Sodium is the main electrolyte present in the ECF while potassium is found in greater 
quantity inside the cell or ICF, therefore, potassium may be important to achieve rehydration 
by helping to retain water in the intracellular space(6). This distribution is important to 
maintain chemical-electrical gradients and ensure the correct function of the cell and its 
electrical communication with the whole body(5). In the first two classifications, dehydration 
(hypotonic and isotonic) is eminently extracellular, since more sodium is lost than potassium, 
yet the last one it is fundamentally intracellular and potassium losses are greater than sodium 
losses(18,19). Regarding the etiology of these classifications, they are shown in Table 5 (20). 
 
Table 4. Dehydration classification with respect to Na+ and water loss and its most common 
etiologies. 
 
Na+ in blood 
H2O loss 
cases 

17 
 
isotonic dehydration 
Normal 
Increased + 
electrolyte loss 
Bleeding, fasting, anorexia, 
vomiting and/or diarrhea. 
hypertonic 
dehydration 
Increased 
augmented 
Diabetes 
insipidus, 
sweating, heat stroke. 
hypotonic 
dehydration 
Diminished 
No loss 
Excessive intake of liquids. 
Source: Escudero, O (2010). Hydration 
 
3.2.3 Fluid requirements in athletes 
The Institute of Medicine (IOM, 2004) published the daily dietary reference for water 
consumption, where the Committee established the recommended daily intake of water for 
children and adolescents, which indicates that children from 1 to 3 years should consume 1.3 
L/day; those 4-8 years old 1.7 L/day; those 9-13 years old 2.4 L/day; male adolescents 
between 14-18 years 3.3 L/day; girls 9-13 years old 2.1 L/day and female adolescents 14-8 
years old 2.3 L/day(twenty-one). If the water deficit is moderate (200 ml/h), water needs can 
be met, but if the deficiency increases, ingestion will be less effective, since the digestive 
absorption of water cannot exceed 800 ml/h. One way to try to speed up the absorption of 
water is to add glucose and sodium.(9). Some practical recommendations are(22): 
• Drink 5 to 7 ml/kg of weight 4 hours before the competition or physical exercise, in 
case of not urinating or dark urine, add 3 to 5 extra ml per kg of weight 2 hours before 
exercise. 
• Immediately before physical exercise consume 200 to 400 ml of drink with a 
concentration of 5-8% HCO. 
• During training consume 1.5 to 3 ml/kg every 15 to 20 minutes during the first hour 
of exercise. 
• In competitions or exercises that last less than 2 hours but are of moderate to vigorous 
intensity, the same drink can be consumed in the final 4 times of the competition. 
• After the competition, if you have lost 2% or more of body mass, you should 
consume more fluids, even if you are not thirsty, recommending 1.2 to 1.5 per kg of 
weight lost during exercise. 

18 
 
 
Although proper hydration should be based on the body weight of each individual; general 
recommendations have been established for practical purposes in clinical practice, such as 
the recommendations mentioned above by the IOM. 
 
3.2.4 Consequences of dehydration 
The loss of body water causes different alterations in the organism for which these alterations 
can suppose a degree of dehydration. It has been shown that dehydration during exercise 
causes significant changes in the physiology of the body's systems: cardiovascular, 
thermoregulatory, metabolic, and endocrine. As a result, the perceived exertion of activity 
may be increased when exercising in a dehydrated state and exercise discontinuation due to 
fatigue is accelerated. The alterations caused by the loss of water and solutes in these systems 
can in turn cause the advancement of fatigue during prolonged exercise, so the most 
outstanding effects of dehydration on a person's body are presented below. When 2% of water 
is lost, the ability to regulate body temperature decreases and there is an increase in 
temperature. With a 3% loss, cramps and dizziness occur and resistance to exercise decreases 
with the possibility of fainting and a greater increase in body temperature that reaches 38°. 
When reaching 4 to 6%, muscle strength decreases, and the muscles suffer contractures. 
Headaches appear and the temperature rises to 39°. When a 7 or 8% level of dehydration is 
reached, contractures are very present, with generalized physical exhaustion, paresthesia’s 
(strange sensations in the limbs, such as cramps, tremors, etc.) with possible organ failure 
and heat stroke. Table 6 shows the physiological effects caused by dehydration in a person's 
body, therefore,(13). 
 
Table5. Physiological responses of the organism to dehydration. 
Gastric emptying rate 
decreases 
Incidence of gastrointestinal upset 
increases 
Splanchnic and renal blood flow 
decreases 
plasma volume 
decreases 

19 
 
Plasma osmolality 
increases 
blood viscosity 
increases 
core blood volume 
decreases 
central venous pressure 
decreases 
Cardiac filling pressure 
decreases 
heart rate 
increases 
stroke volume 
decreases 
minute volume 
decreases 
Sweat rate at a given core temperature 
decreases 
Internal temperature at which sweat appears 
increases 
Maximum sweat rate 
decreases 
Skin blood flow at a given internal temperature 
decreases 
Internal temperature at which skin blood flow increases 
increases 
Maximum blood flow to the skin 
decreases 
Core temperature at a given exercise intensity 
increases 
Muscle glycogen utilization 
increases 
Endurance performance (simulated races) 
decreases 
Endurance capacity (exercise to exhaustion) 
decreases 
Source: Merida, WTO (2010). The importance of hydration in sport. 
3.3 
Physical exercise as an important factor of dehydration 
It is important to establish the difference between PA and physical exercise (PE). PA is 
understood as any bodily movement that increases energy expenditure(23). On the other 
hand, PE is planned, structured, repetitive and purposeful physical activity with the final or 
intermediate objective of improving or maintaining physical condition.(24). During AF or 
EF, coupled with weather conditions, the muscles generate a large amount of heat that must 
be dissipated. This heat production by the muscles is proportional to the intensity of the work, 
so that in activities of short duration and high intensity (team sports) as those of longer 
duration and lower intensity (half marathon, marathon, cycling stages, triathlon, etc.) carried 
out in adverse temperature conditions, represent a risk of heat-induced injuries and, in turn, 

20 
 
this physiological process induces a loss of fluids and minerals in our body (dehydration), 
which we have to recover to establish organic homeostasis(25). 
3.3.1 Types of physical exercise 
There are two main types into which we can classify physical exercise, which are the aerobic 
type and the anaerobic type. Aerobic exercises are also known as dynamic exercises, within 
this classification, are low and medium intensity exercises, which are commonly used to lose 
weight, since it allows you to burn fat more quickly, for example, cycling, run or swim. By 
putting this method (aerobic) into practice, the body has a higher oxygen consumption, helps 
prevent cardiovascular diseases, lower blood pressure, cholesterol levels and blood glucose. 
On the other hand, anaerobic exercise, also known as "static", deals with those physical 
activities that require more effort, characterized by being of high intensity, such as lifting 
weights or another type of activity for skeletal muscle toning; are carried out in short series. 
The benefits it provides list the improvement of flexibility, elasticity and resistance of the 
body, this due to the repetitions of the exercise, as well as reducing the amount of fat and 
strengthening the joints(26). There are many different types of physical activity that serve to 
develop various aspects of physical fitness. The most important types of physical activity for 
child and youth health are activities related to cardiovascular (aerobic) work, those related to 
strength and/or muscular endurance, flexibility and, lastly, coordination exercises.(27). The 
global recommendations of the World Health Organization (WHO) suggest that children and 
adolescents should spend at least 60 minutes a day in physical activities of moderate to 
vigorous intensity, mainly aerobics, and perform muscle and bone strengthening activities, 
at least 3 times a week(28). 
3.3.2 Exercise intensity 
The measurement of the quantity and quality of AF or EF has become increasingly important, 
for this, accelerometry seems the most reliable objective instrument, that is, valid and 
reproducible to be able to measure the intensity of the exercise, however, a drawback of this 
instrument or technique is hardly applicable for clinical use, in primary care practice, office 
or other settings. On the other hand, epidemiological studies require a large number of 
subjects, resulting in a cost problem.(29). Intensity involves time and volume and is classified 

21 
 
with respect to the energy required based on the basal energy. There are simpler (reliable and 
inexpensive) methods to measure exercise intensity, for example, the metabolic equivalent 
task or MET for its acronym in English. METs is the unit used to describe the energy 
expenditure of a specific activity with respect to the expenditure at rest, for example, a MET 
is the energy index considered for the energy expenditure at rest, therefore an activity of 3 
METs means an expenditure 3 times higher than the energy at rest(24). Tables 7 and 8 show 
the classification of intensity in PA and intensity performed by sport, respectively. 
 
Table6. Classification of PA and its intensity with respect to the METs used. 
intensity level 
Absolute intensity: 
METs 
Relative intensity: perception scale, 
where 0= rest and 10=maximum effort. 
Short 
1.1-2.9 
 
moderate 
3.0-5.9 
5-6 (45-64% aerobic capacity) 
vigorous 
6.0 METs or more 
7-8 (65-84% aerobic capacity) 
Source: Boullosa, B & Casas, I (2011). Physical activity for health. In: nutrition applied to sport. 
 
Table7. Intensity classification according to the METs used in each sport per 1 hour of 
PA(30). 
Exercise 
MET 
Classification 
Yoga (Surya Namaskar) 
3.3 
moderate 
Baseball 
4.0 
moderate 
Golf 
4.3 
moderate 
volleyball 
4.5 
moderate 
Dance (Jazz, Ballet) 
5.0 
moderate 
Basketball 
6.5 
vigorous 
Playing football (soccer) 
7.0 
vigorous 
Jogging 
7.0 
vigorous 
Running (7.5Km/H) 
13.0 
vigorous 

22 
 
Bicycle (heavy duty) 
14.0 
vigorous 
Swimming (vigorous pace) 
15.6 
vigorous 
Running (10Km/H) 
16.0 
vigorous 
Source: Muntané, M (2017). How to measure exercise intensity: METs. 
According to the previous tables (Tables 7 and 8), it was considered unnecessary to use an 
accelerometer, heart rate or oximetry instrument since the exercise to be performed is already 
categorized as vigorous intensity. 
 
3.3.3 Prevalence of dehydration in athletes 
During PE in a cool, dry environment, sweat loss can be as little as 250 milliliters per hour; 
on the contrary, in a hot and humid environment, the amount of sweat of a physically trained 
and well-acclimatized athlete can exceed 2,500 milliliters per hour. Due to climatic 
conditions, exercise, hydration habits and chronic-degenerative diseases, it is difficult to 
determine the prevalence of dehydration in the general population due to the constant changes 
in composition since it is a dynamic process and varies in each individual(31). Dehydration 
is cumulative, in other words, it is understood as a progressive process of the athlete in 
successive days of physical exercise if he does not hydrate completely.(Two). 
 
3.4 
Factors that alter hydration status 
 
3.4.1 Obesity 
 
Childhood obesity has emerged as one of the main public health problems, alarmingly 
increasing its prevalence and its multiple and serious comorbidities. The term obesity refers 
to an excess of body fat.(32). In the last three decades, the prevalence of global overweight 
and obesity has increased worldwide, with an estimated 170 million children (under 18 years 
of age) due to sedentary lifestyle and poor eating habits(33). Therefore, it is imperative to 
consider exercise and physical activity as prevention and a way to combat the epidemic of 
childhood obesity.(3. 4). The 2018 Health and Nutrition Survey has reported a combined 

23 
 
prevalence of overweight and obesity in the population aged 12 to 19 years of 38.4%, where 
overweight was 23.8% and obesity 14.6%, that is, it increased 3.5% with respect to the data 
of 2012 in the combined prevalence. Taking into account the premise that the ACT in the 
organism can vary between 55% and 70% in individuals due to the different characteristics 
of body composition(35), that is, the water content in fatty tissue is approximately 10–15%, 
while in muscle tissue it is approximately 75%, so the aqueous fraction of body mass varies 
inversely with the degree of obesity . This value is much lower when calculated as the fraction 
of lean mass where skeletal muscle tissue contains more than 75% water.(3). 
 
 
3.4.2 Climate 
 
In the state of Colima there are 4 types of climates, predominantly the warm sub-humid 
climate in 78.52%, with 12.42% of its territory presenting dry and semi-dry climate, on the 
other hand, the semi-warm sub-humid climate has 7.58% of the territory, and In the northern 
part of the state, on the slopes of the Colima Volcano, the temperature decreases, so it 
presents a Subhumid Temperate climate with the minimum percentage of 1.48%. The 
average annual temperature is 25°C with maximum temperatures greater than 30°C and 
minimum temperatures of 18°C, as shown in table 9.(36). 
Table8. Area of the state of Colima by type of climate and annual temperature in °C. 
Type or subtype 
Symbol 
Total R 
Warm sub-humid with summer rains 
A(w) 
78.52 
Semi-warm sub-humid with rains in summer 
AC 
7.58 
Subhumid temperate with summer rains 
C(w) 
1.48 
Very warm and warm semi-dry 
BS1(h') 
12.42 
Station 
Period 
Average 
temperature 
coldest 
temperature 
hottest 
temperature 
Cuauhtémoc 
1981-2016 
23.7 
21.4 
25.5 
Manzanillo (observatory) 
1961-2016 
26.6 
20.3 
33.0 
Callejones 
1946-2016 
26.6 
23.5 
29.3 

24 
 
Comala ETA 
1987-2016 
24.3 
22.9 
26.1 
Los Otates veladero 
1966-2016 
25.1 
21.5 
26.7 
Colima (observatory) 
1966-2016 
25.6 
23.8 
28.1 
Minatitlan 
1965-2016 
23.2 
21.3 
26.3 
Armory 
1948-2016 
26.6 
23.5 
28.7 
Source: National Water Commission. Monthly record of average temperature in °C. 
 
Weather conditions are a strong factor in altering hydration status, especially in climates with 
high temperatures. In hot climates (31 to 32°C) the rate of sweating increases and therefore 
dehydration of 2% of body weight can be obtained in 60 min of intense exercise, reducing 
sports performance in addition to reducing cognitive/mental performance(5).Any rise in 
ambient temperature of 1 ºC greater than 30 ºC increases water requirements (30 ml/kg). If 
the heat is extreme and sweating is very important, the feeling of thirst is not as intense as it 
would correspond to the greater need for water, so it should be prevented by considering the 
amount and type of drink(9). Extreme environmental conditions (both hot and cold) represent 
a challenge to the body's thermoregulatory mechanisms and cause serious damage to the 
health of the athlete, for this reason it is essential to establish adequate hydration guidelines 
to improve and prevent possible problems, as well as how to increase sports performance 
The main cardiovascular and thermoregulatory adaptations occur during the first few days of 
training in the heat, with full adaptation being achieved within 14 days. However, 75% of 
physiological acclimatization responses occur by the end of the first week. To do this, it is 
necessary to train in hot environments at temperatures between 25-35ºC, intensities between 
60-75% of VO2max (above the Aerobic Threshold),(25). 
 
3.4.3 Feeding Habits 
 
Within the branch of medicine, specifically nutrition, hydration has become a leading country 
in Spain, a science in itself. One of the most pioneering and representative definitions of 
hydration is "the contribution of water, as an essential non-caloric nutrient, from food and 
beverages"(8). Studies have shown that athletes can recover the fluid lost by sweating during 

25 
 
training or competition, which shows that this problem is a voluntary cause. Some of the risk 
factors for dehydration are the daily eating and hydration habits and the state of hydration 
with which they arrive at the practice, secondly, the lack of hydration or insufficient 
hydration during this time(37). Some of the guidelines on daily water needs have shown that 
children and adolescents drink less than the adult population, coupled with their low 
consumption of foods high in water (fruits and vegetables) since children do not feel the need 
to drink enough amount of water to replenish the loss of liquids lost during prolonged 
exercise, making them more susceptible to dehydration, this being the main cause of the 
excessive increase in body temperature, which predisposes the person to suffer from heat 
stroke(21,38). 
 
3.5 
Diagnostic methods of dehydration 
 
Selection of an appropriate hydration assessment method is a controversial aspect of fluid 
balance science. All hydration assessment techniques vary greatly in their applicability due 
to methodological limitations such as the circumstances required for measurement 
(reliability), ease and cost of application (simplicity), sensitivity to detect small but 
significant changes in the state of hydration (accuracy) and the type of dehydration 
expected(39). Hydration status is difficult to measure because it is a dynamic process; that 
is, it is constantly modified and varies in each person. Another problem is that in many tests 
to measure hydration status, what is actually examined is "the variation" rather than the 
absolute degree of hydration.(31). When greater precision of acute changes in hydration is 
sought, plasma osmolality, isotope dilution, and changes in body mass, used in an appropriate 
context, provide the precise gradation of measurements frequently required in scientific 
research.(Twenty-one). Table 10 shows defined thresholds for complex and simple indicators 
of hydration recommended in athletes to guide the distinction between euhydration and 
dehydration. For the present study, 3 indicators will be used (GEO, change in ACT and 
change in body mass) where the fluid balance will be considered adequate when the results 
of any two evaluations are consistent with the euhydration thresholds (Table 10).(39). 
 

26 
 
Table9. Cut-off points for euhydration in the different indicators. 
Evaluation technique 
Practicality for the 
athlete 
Acceptable euhydration cutoff point 
Change in total body water (L) 
Short 
<2% 
Plasma osmolality (mOsm) 
Half 
<290 
GEO (g/mL) 
high 
<1,020 
Urine osmolality (mOsm) 
high 
<700 
Urine color (#) 
high 
<4 
Changes in body mass (kg) 
high 
<1% 
Source: Cheuvront, SN (2005). Evaluation of hydration in athletes. 
 
3.5.1 Gold standard 
The combination of total body water by estimation of the dilution of trace amounts of an 
isotope (usually deuterium oxide, 2H2O) and plasma osmolality provides the "gold standard" 
for hydration assessment. higher accuracy and reliability(39,40). The isotope dilution method 
is the most accurate and widely used way of determining ACT. The word isotope (“same 
place”) of an element in the periodic table refers to an element that differs from the parent 
element in atomic weight without affecting chemical properties. Despite being an easy 
method to perform and not using radiation, it is a time-consuming and expensive study. This 
makes it hardly applicable in clinical practice, although being the reference method for 
estimating body water, it can be used to confirm the data obtained by simpler methods.(41). 
Blood plasma osmolality accurately identifies a person's hydration status and is sensitive to 
changes in hydration status, during acute dehydration and rehydration.(40). Plasma 
osmolality is determined by the concentrations of sodium, potassium, glucose and urea 
nitrogen and its calculation is obtained with the following formula: 
• Plasma osmolarity = 2(Na+ + K+) + glucose/18 + BUN/2.8 
Normal plasma osmolality is between 280 and 295 mOsmo/L(42). These “gold standards” of 
hydration assessment are good for sports science, medicine, or benchmarking, but because 
they require considerable methodological control, they are expensive, and they require skill. 

27 
 
analytical, they are not of practical use for monitoring hydration status on a day-to-day basis 
during training or competition(39). 
3.5.2 Urine Specific Gravity (USG) 
GEO or urinary specific density is a technique (whose collection, conservation and analysis 
are described in Annex 1) that measures the concentration of particles in urine and the density 
of urine compared to that of water. Measuring GEO is an easy and convenient method of 
estimating a patient's hydration status as well as the functional capacity of their kidneys.(43). 
Urinalysis is a frequently used clinical measurement to distinguish between normal and 
pathological conditions. Urinary indicators of dehydration include decreased urine volume, 
high UGE, high urine osmolality (OOsm), and dark urine color (OCol).(39). Normal GEO 
results in adults’ range between 1010 and 1020 gr/cm3. Abnormal results are usually those 
below 1,010 or above 1,020(43). A child is relatively hydrated when the density is less than 
1010g/l and relatively dehydrated when it is greater than 1020g/l. Urine with a urinary density 
of less than 1010g/l is called hyposthenuria, isosthenuria with a urinary density of 1010-
1020g/l, and hyposthenuria with a urinary density greater than 1020g/l. The GEO results can 
classify the level of dehydration that a person may have as shown in table 11(44). 
Table eleven. Hydration status with respect to GEO. 
GEO (g/cm³) 
Hydration Status 
>1,030g/cm³ 
severe dehydration 
1,020 to 1,030 g/cm³ 
moderate dehydration 
<1,020g/cm³ 
Euhydrated 
Source: Lozano, Triana (2016). General urine test: a useful test in children. 
 
3.5.3 Total Body Water Loss by bioimpedance (PACT) 
Numerous methods are known to estimate ACT, including bioimpedance, anthropometry, 
and the use of stable isotopes. Another estimation formula, widely used clinically, is the 
calculation of 60% of body weight or (Kg)*0.6(41). ACT loss is one of the most reliable 
indicators to measure and diagnose the degree of dehydration. There are two techniques to 
measure total body water, which can be isotope dilution or can be estimated by BIE(40). This 
is a technique that in some research is recommended as a method that accurately estimates 

28 
 
the hydration status of a person, however, the EIB is not a good method if it is used as a 
reference criterion or isolated, it can already show contradictory results(39). The BIE is an 
indirect technique to estimate body composition using the ACT with its advantages of being 
simple, fast, and non-invasive. By deduction of the water constants of the tissues, the fat-free 
mass (FLM) is obtained and by derivation, the fat mass (FM), through the equation based on 
two components (FFM kg = total weight kg – MG kg). These 2 vectors would agree with the 
equation Z2 = R2+ Xc2. The R represents the resistance of the tissues to the passage of an 
electric current and Xc is the additional opposition due to the capacitance of those tissues and 
cell membranes (it is the so-called dielectric component), and these values depend on the 
frequency of the electric current. .(Four. Five). 
 
 
Figure3. Graphical derivation of the phase angle and its relationship with the resistance ®, 
the reactance (Xc) and the impedance (Z). 
Source: Alvero-Cruz JR; et al. (2011). Electrical bioimpedance as a method for estimating body composition, 
practical rules of use. 
 
EIB can be affected by many different situations that must be considered, such as: body 
position, hydration, intake of food and drink, ambient air and skin temperature, recent 
physical activity and the conductance of the place where it is performed. Physical activity 
increases cardiac output and vascular perfusion, with a subsequent increase in blood flow to 
the muscle, as well as an increase in muscle and skin temperature, resulting in a decrease in 

29 
 
muscular endurance and an overall decrease of body impedance(Four. Five). The degree of 
dehydration can be classified based on the loss of ACT as shown in table 12(46). 
Table10. Hydration status with respect to ACT loss by bioimpedance. 
Percentage of water loss. 
Hydration Status 
>7% 
severe dehydration 
4 to 6% 
moderate dehydration 
2 to 3% 
mild dehydration 
<2% 
Euhydrated 
Source: Cirigliano, H (2018). Hydration and physical activity. 
 
3.5.4 Total Body Mass Loss (TWBC) 
Rapid and accurate estimation of changes in fluid balance is very important. It is difficult to 
determine the total volume of water with precision in each case, but an extremely useful and 
sensitive indicator of changes in body water content is the daily measurement of body 
mass.(3). Likewise, the percentage of weight loss is a good indicator of the state of hydration, 
classifying the state of hydration according to the percentage of body mass lost, as shown in 
Table 13. A loss of 1% of body weight causes a decrease 2.5% in plasma volume and 
represents mild dehydration(twenty-one). Acute changes in hydration are calculated as the 
difference in body mass before and after exercise and the percentage lost is subsequently 
calculated. The level of dehydration is best expressed as a percentage of initial body mass 
rather than a percentage of ACT, since the latter varies widely. The use of this technique 
implies that 1 g of mass lost is equivalent to 1 mL of body water lost.(39). The formula to 
calculate the percentage of weight lost considers the initial weight (Pi) and final weight (Pf), 
expressed as follows: 
• (Pi – Pf) * 100/ Pi 
 
Table11. State of hydration with respect to the percentage of weight loss (%PP). 

30 
 
Weight change percentage 
Hydration Status 
>5% 
severe dehydration 
3.1% to 5% 
moderate dehydration 
>1% to 3% 
mild dehydration 
< or equal to 1% 
Euhydrated 
Source: Mayol, L (2011). Thermoregulation and hydration in exercise. In: Nutrition applied to sport. 
 
3.6 
Hydrating drinks 
With the advances in science and technology, new forms or strategies of sports preparation 
called ergogenic are born, which seek an improvement in physical capacity reflected in better 
sports performance. Ergogenic aids include substances, methods, drugs, equipment, and the 
improvement of those innate or acquired conditions. These aids are divided into non-
nutritional and nutritional. Nutritional ergogenic aids include micronutrient supplementation 
and macronutrient supplementation in which hydrating drinks are included.(47). Hydration 
drinks are drinks that contain water, glucose and electrolytes to replenish the loss of liquids 
and mineral salts, in addition, they regulate body temperature, lubricate the joints and 
facilitate the absorption and transport of the nutrients necessary to obtain energy(48). In 
Mexico, the Federal Consumer Protection Agency (PROFECO) in the moisturizing beverage 
market has been classified into three different groups (Table 6). 
 
 
Table12. Classification of hydrating drinks 
type of drink 
Characteristic 
sports drinks 
Made with the dissolution of mineral salts, sweeteners, or 
other ingredients in order to replenish the water, energy and 
electrolytes lost by the human body during exercise. 
rehydration drinks 
These types of products are solutions that contain electrolytes 
without sugars. 

31 
 
oral electrolytes 
According to the General Health Law, in its article 226 
section VI, they are "medicines that do not require a 
prescription to be purchased and that can be sold in 
establishments other than pharmacies", and that generally 
contain glucose and electrolytes, such as sodium and 
potassium. 
Source: Characteristics of the types of hydrating drinks according to PROFECO. Adapted from "Moisturizing 
Drinks", by PROFECO, 2018. 
 
3.6.1 Oral electrolytes 
 
According to the General Health Law, in its article 226 section VI, oral electrolytes can be 
defined as "medications that do not require a prescription to be purchased and that can be 
sold in establishments other than pharmacies", and that generally contain glucose and 
electrolytes, such as sodium and potassium(49). Being classified as a medicine, its use is 
based on the prevention and treatment of dehydration of different causes, mainly vomiting 
and diarrhea. Its administration provides sufficient amounts of water, sodium, chloride and 
potassium necessary to compensate for the losses in many mild to moderate cases that do not 
require parenteral therapy, and thus restore the fluid and electrolyte balance.(Fifty). Based 
on the results of a meta-analysis, in 2002, the WHO changed the formulation of oral 
rehydration salts to a lower osmolality (245 mosmol/kg) with a lower glucose concentration 
(13.5 g/L [75 mmol/L]. l]) and sodium (75 meq/L) while maintaining a 1:1 molar ratio of 
sodium and glucose. This new formula replaces the original, and is the only one used 
worldwide by the WHO(51). Currently the solution for oral hydration is constituted (in g/L) 
by: 3.5 sodium chloride, 2.9 trisodium citrate dihydrate, 1.5 potassium chloride and 20 
glucose. This solution provides (in mmol/L): sodium 90, chlorine 80, potassium 20, citrate 
10, and glucose 111 (total osmolality, 311 mosm/L). The administration and dose of oral 
electrolytes in children under two years of age consists of giving the necessary spoonful in a 
24-hour period. Not to exceed 1200 ml in 24 h. In older than two years, the necessary 
tablespoons in a period of 8 to 24 hours. Thirst is a good guide to restore the required 
volume(fifty). 

32 
 
Hydrating drinks of any kind are consumed mostly by sportsmen or athletes, since they were 
designed to delay the depletion of glycogen stores during training or physical exercise, 
providing sufficient carbohydrates to maintain glucose levels in blood in addition to 
replenishing essential electrolytes such as sodium and potassium, which promote fluid 
retention and help prevent dehydration and are often more easily lost through sweat(52). 
 
3.6.2 Disadvantages of using industrialized beverages 
 
The prevalence of overweight and obesity in Mexico has been related to the high 
consumption of hyperenergetic beverages that are sweetened with added sugars, favoring 
positive energy balances that result in an increase in body weight(1). According to a study 
by the National Institute of Public Health of Mexico (INSP), beverages provide more than 
20% of the calories in the Mexican diet, although it is recommended that they do not exceed 
10%. In addition, 70% of the added sugars consumed by Mexicans come from sugary drinks, 
which has caused a serious problem of overweight, obesity and diabetes in our country.(53). 
Studies conducted by the University of Birmingham have found that sports drinks wear down 
the tooth enamel and dentin beneath them. Its high levels of acidity imply that the wear of 
tooth enamel is 30 times greater compared to plain water. Drinking these drinks during 
exercise worsens the situation since, since there is a shortage of saliva, there is no buffer 
against the acidity of the drink.(Two) in addition, the influence of advertising on the diet of 
children and adolescents that favors the consumption of foods and beverages with a high 
content of sugars, fats and/or sodium, directly linked to obesity. In another cohort study of 
adolescents in the USA, the research focused on the consumption of sports drinks and its 
relationship with weight gain. Each daily serving of sports drink was found to predict a 0.3-
point increase in BMI in women and 0.33 in men. Therefore, its consumption was associated 
with greater weight gain and risk of obesity.(54). 
 
3.6.3 Coconut water 
 

33 
 
The coconut plant belongs to the Arecaceae family, whose scientific name is Cocos nucifera 
and commonly known as coconut palm. It is a plant native to the Pacific Islands, and today 
cultivated throughout the tropics. It is the most cultivated and important palm in the world, 
since it is currently the main species that produces vegetable fat. It is one of the plants that 
provides the greatest diversity of products in the world, being a primary source of food and 
drink.(55). In Mexico, the commercial cultivation of coconut palms is over a hundred years 
old and for decades it was the engine of the economy of the coastal regions of the Pacific 
(Guerrero, Colima, Oaxaca, Michoacán, Sinaloa, Jalisco and Chiapas) and the Gulf and 
Caribbean (Tabasco, Veracruz, Campeche, Yucatan and Quintana Roo)(56).Coconut water 
is the liquid found naturally inside the fruit surrounded by the pulp of the coconut. It is 
transparent in color, sometimes a little opaque, and has a characteristic sweet flavor when it 
reaches its ripening point.(53). Coconut water has a low caloric value, however, most of its 
composition is sugars, and it is considered a natural isotonic drink, being highly appreciated 
for its little manipulation since it is taken by extracting it directly from the fruit, which is why 
it is recommended among athletes for promote recovery after physical activity. This food 
also has antioxidant properties that help delay cell aging.(55). 
 
3.6.4 Chemical composition of coconut water 
 
Coconut water can vary by species, place of origin and maturity of the coconut (young or 
green coconut water is fresher and more functional)(53). The average nutritional composition 
is shown in table 15. 
 
Table fifteen. Average nutritional contribution of natural coconut water in 100 ml. 
Component 
Coconut water 
Energy (kcal) 
twenty 
Proteins (gr) 
0.1 
HCO (gr) 
5.5 
Lipids (gr) 
0.05 
Sodium (mg) 
25 

34 
 
Potassium (mg) 
160 
Chlorine (mg) 
twenty 
Calcium (g) 
5 
Phosphorus (mg) 
0.4 
Magnesium (mg) 
0.45 
Source: FAO. 
 
The chemical composition of coconut water is affected by several factors. Coconut water 
from different varieties of coconut contains different concentrations of compounds, and since 
the chemical content also varies in addition to the different stages of maturity, the soil and 
environmental conditions also affect its composition.(57). Coconut plantations are 
established in the coastal zone, on sandy soils, poor in organic matter and N. The soil has a 
sandy texture with 90.92, 3.28 and 5.80% sand, silt and clay, respectively. The low 
productivity results in low income per unit area, so the application of appropriate fertilizers 
is a viable alternative to increase the yield of the coconut crop using essential elements such 
as N and K, giving variability to the chemical composition of the coconut, especially in you 
go out(58). A study carried out in Brazil showed that the physical properties of AC were 
affected by the variable application of nitrogen and potassium(57). The differences in the 
concentration of potassium and salts (WHO/UNICEF) contain 20 mmol/L and the green AC 
ranges between 32.6 and 53.5 mmol/L(59). 
Currently AC has been widely studied since it contains electrolytes and an osmolality similar 
to that of intestinal content, which facilitates its absorption, reducing the possibility of 
dehydration.(53). AC contains cytokinin that promotes cell regeneration, in addition, its high 
content of potassium and other electrolytes promotes adequate blood pressure, helping to 
prevent heart disease. This electrolyte (K+) is extremely important for the prevention and 
treatment of dehydration, since losses are high and if not corrected it can aggravate 
dehydration, so coconut water can be used as a moisturizing and rehydrating solution due to 
its content of this electrolyte(53.59), has also been used successfully in various parts of the 
world as a therapy for oral rehydration, treatment of childhood diarrhea, gastroenteritis and 
cholera(60). Other applications and benefits of coconut water are: 

35 
 
• Its consumption in fresh represents an important source of energy for the human 
organism, but in addition the pulp offers is a protagonist in the elaboration and 
manufactures of confectionery. 
• Coconut water is used as a refreshing drink and as an ingredient for stews, ice cream 
and dishes. 
• In the beekeeping sector it plays an important role, as the flowers are excellent food 
for bees. 
• In medicine it has many applications, among which are: antiseptic, astringent, 
bactericide, diuretic, etc. 
• In many tropical countries it is used as a popular remedy against asthma, bronchitis, 
bruises, burns, constipation, dysentery, cough, fever, flu, etc. 
Within all these uses and benefits of coconut and coconut water, it should be kept in mind 
that the best way to consume coconut is fresh (freshly cut and opened).(53). 
Although AC is already well studied in terms of its chemical content, there may still be 
unknown solutes that contribute to its special biological effects. With the development of 
more advanced detection techniques, the detection can be intensified to detect new 
compounds of medicinal value present in it, therefore, future studies should be carried out to 
determine the factors that produce the desirable chemical composition for a specific purpose. 
Breeding studies can also be carried out to produce AC enriched with specific chemical 
compounds(57). 
 
3.6.5 Chemical comparison between oral electrolytes, Coconut water and Electrolit® 
 
Table13. Chemical comparison between powdered oral electrolytes, Coconut Water and 
Electrolit® per 100 ml. 

36 
 
 
oral electrolytes 
Coconut water 
Electrolit® 
Energy (kcal) 
8 
22 
twenty 
Proteins (gr) 
- 
0.1 
- 
HCO (gr) 
two 
5.5 
5 
Lipids (gr) 
- 
0.05 
- 
Sodium (mg) 
35 
25 
12 
Potassium (mg) 
150 
160 
149 
Chlorine (mg) 
284 
twenty 
106 
Calcium (g) 
- 
5 
0.03 
Phosphorus (mg) 
- 
0.4 
- 
Magnesium (mg) 
- 
0.45 
14.2 
Own source 
 
4 
BACKGROUND. 
There are currently few studies on the effect of CW on hydration status in athletes, in addition 
to being studies on adults, since the bibliography on the comparison of beverages (coconut 
water vs. sports drink) is almost null, and it is null when comparing oral electrolytes. 
In a study conducted by Castro-Sepúlveda, et al. 2015 in Chilean professional soccer players, 
a prevalence of dehydration of 98% was reported by Urine Specific Gravity (USG) before 
training, of the 156 athletes evaluated, only one subject (0.6%) presented euhydration 9% (14 
subjects) showed mild dehydration, 76.9% (120 subjects) moderate dehydration, and 13.5% 
(21 subjects) severe dehydration(61)so this study clearly shows us the lack of habits in terms 
of hydration. Cheuvront S. and Sawka M. in their 2005 study that aimed to evaluate several 
common methods for assessing hydration status found that although measurements of plasma 
osmolality and total body water are currently the best assessment measurements of hydration, 
there is currently no consensus to prefer any proposal over the other in sports contexts. In 
most circumstances, the use of body mass measurement combined with some measurement 
of urine concentration (USG, OOsm, and OCol), offers a simple method of evaluation and 
allows a wide sensitivity to detect significant deviations in urine concentration. fluid balance 
(>(39). In the Yucatan Peninsula, Mexico, Pérez NGU carried out a study in 2014 where the 

37 
 
consumption preferences of coconut derivatives (tuba, coconut water and virgin coconut oil) 
were evaluated through sensory tests, surveys, and tastings at food events. Dissemination, 
with the main objective of contributing to the knowledge of the behavior of the coconut palm 
consumer and, specifically, of tuba, virgin oil, and coconut water, where an acceptance of 
93.9%, 94% and 87% respectively was obtained. Both consumers and non-consumers of 
coconut water expressed their interest in incorporating bottled coconut water into their habits. 
52.67% reported that they would do it weekly, among the factors they mentioned, the flavor 
and nutritional properties stand out.(56). 
Among the studies carried out where AC is compared with other hydrating drinks is the study 
by Saat, M, et al. 2002 which is entitled "Rehydration after exercise with fresh young coconut 
water, carbohydrate-electrolyte beverage and plain water" where 8 healthy subjects aged 22.4 
± 3.3 years were included with the aim of comparing plain water, coconut water and beverage 
with carbohydrates and electrolytes. To measure rehydration status, they used blood samples, 
urine samples, and evaluated body mass before and after exercise. A volume of liquids 
equivalent to 120% of water loss was administered, dosed as follows: 50% before exercise 
(781 ± 47 ml), 40% during exercise (625 ± 33 ml) and 30% post exercise (469 ml). ± 28 ml) 
resulting in 120%. The drinks were administered randomly. The percentage of weight lost 
and regained after rehydration was not statistically significant in the different sessions. On 
the other hand, blood volume was measured, and fluid restoration was much better with 
coconut water, although it was not statistically significant between the other two drinks used. 
The accumulated urine was not different between the sessions, in addition to there being no 
difference with the osmolality of sodium and chloride in serum, the only significant thing 
was the concentration of plasmatic glucose that was elevated compared to plain water when 
the periods of hydration were with coconut water and sports drink On the other hand, blood 
volume was measured and fluid restoration was much better with coconut water, although it 
was not statistically significant between the other two drinks used. The accumulated urine 
was not different between the sessions, in addition to there being no difference with the 
osmolality of sodium and chloride in serum, the only significant thing was the concentration 
of plasmatic glucose that was elevated compared to plain water when the periods of hydration 
were with coconut water and sports drink On the other hand, blood volume was measured 
and fluid restoration was much better with coconut water, although it was not statistically 

38 
 
significant between the other two drinks used. The accumulated urine was not different 
between the sessions, in addition to there being no difference with the osmolality of sodium 
and chloride in serum, the only significant thing was the concentration of plasmatic glucose 
that was elevated compared to plain water when the periods of hydration were with coconut 
water and sports drink(62). On the other hand, the study entitled “Coconut Water Does Not 
Improve Markers of Hydration during Sub-Maximal Exercise and Performance in a 
Subsequent Time Trial Compared to Water Alone” was carried out with the purpose of 
comparing markers of hydration during sub-maximal exercise and performance. Of sub-
maximal exercise and subsequent to the study time consuming plain water or coconut water. 
There was also a secondary objective which evaluated coconut water palatability during 
exercise and voluntary consumption during vigorous exercise. Ten men aged 27.9 ± 4.9 
years, body mass 78.1 ± 10.1 kg, and mean maximum minute of power 300.2 ± 28.2 were 
evaluated completing 60 minutes of submaximal cycling, followed by 10 km against the 
clock on two occasions. During the tests, the participants consumed plain water or coconut 
water randomly, drinking 250 ml of the assigned drink between 10-15 min, 25-30 min and 
40-45 min, and then drinking at will from minute 55 until finishing. The proof. Body mass 
and urine osmolality were recorded before exercise and then after 30 min, 60 min, and after 
the time trial. During each drink period, blood glucose, lactate, heart rate, rate of perceived 
exertion (RPE; 6-20), and ratings of thirst, sweetness, nausea, satiety, and upset stomach (1 
= very high) were recorded. Low / not at all, 5 = very high). Coconut water did not 
significantly improve time trial performance compared to water alone (971.4 ± 50.5 and 
966.6 ± 44.8 seconds, respectively; P = 0.(63). 
It is important to note that a very low sample size was used in both studies, so studies with a 
larger sample size are required to allow us a more accurate or adequate determination of the 
effects on our study variables. In addition, it should be noted that both studies were carried 
out in the adult population, unlike the present research work, which will work with the 
pediatric population, who, due to their different physiological characteristics, could yield 
different results. 
 

39 
 
5 
PROBLEM STATEMENT 
 
The objective of sports-related nutrition is to cover all stages related to sports, including 
training, competition, recovery, and rest. Proper hydration, especially in pediatric stages, 
benefits sports performance and is crucial for health, since during physical exercise, children 
are at greater risk of dehydration due to their physiological characteristics that make them 
less effective at eliminating heat. bodily(two)In addition, due to the established 
recommendations, where children should perform at least 60 minutes of moderate or vigorous 
intensity aerobic physical activity per day, it is necessary to emphasize that dehydration 
according to Bean A. 2010, in the complete athlete's guide, mentions that it is cumulative, so 
if children and adolescents do not receive proper daily hydration, the risk of suffering a higher 
degree of dehydration increases(2.28). Hydration is an aspect that should not be taken lightly 
by health personnel and by personnel who remain in contact with children when they perform 
physical exercise within their sport, this personnel includes parents, teachers or coaches(12). 
There are currently multiple beverage options available to the consumer, including isotonic 
beverages. These drinks, thanks to their content of carbohydrates and electrolytes (mainly 
sodium), contribute to maintaining the athlete's hydration at all stages of training and/or 
competition (before, during and after). Keep in mind that plain water is not the ideal beverage 
for post-exercise rehydration when rapid and complete restoration of fluid balance is 
necessary and where all consumption is in liquid form. Plain water ingestion after exercise-
induced dehydration of 4% of body mass causes a large decrease in plasma osmolality 
followed by copious diuresis.(6). In recent years, a new technique for using these drinks has 
been developed that consists of rinsing the mouth with them and then expelling the liquid 
without ingesting it. Although it is still under study, the purpose of this technique is to obtain 
the benefits of sports drinks, avoiding some of the adverse effects derived from their 
ingestion. The problem with the wide range of beverages available to the consumer is the 
lack of knowledge on the part of the latter of how to use them correctly, which can lead to 
the appearance of adverse effects derived from misuse or excessive consumption.(52). 
 

40 
 
6 
JUSTIFICATION 
 
The purpose of this study is to compare the hydration effects of CW as an alternative drink 
to industrial EOs in adolescents who perform physical exercise. Currently there are no studies 
that have evaluated CW in adolescent athletes, so this study can generate knowledge of this 
drink in an unstudied population. 
Water is the most abundant component of the human body, which by itself is unable to 
produce in sufficient quantities to satisfy its needs; That is why it is vital to consume an 
adequate amount to maintain homeostasis, since small changes in the water balance can cause 
important modifications in metabolic processes.(4). This non-caloric nutrient is involved in 
almost all functions of the human body, particularly important in thermoregulation and 
physical and cognitive performance.(10) On the other hand, a lack of hydration has 
disadvantages and these are more evident when carrying out prolonged or high-intensity 
exercise in hot conditions. A deficit of less than 2% of the athlete's body mass has been shown 
to decrease exercise capacity and performance by detectable amounts. It has been commonly 
reported that performance declines when the individual becomes dehydrated to as little as 
2% of body weight, and that losses in excess of 5% of body weight can decrease work 
capacity by approximately 30%.(37). Experts indicate that regular consumption of water 
maintains good health and even helps prevent non-contagious diseases related to nutrition, 
so the absence of this nutrient can be fatal in days. children who play sports in hot climates 
such as the state of Colima, they are especially susceptible to the development of involuntary 
dehydration(4). The sweating rate is lower in children, for this reason their core temperature 
increases to compensate for the production of sweat, causing heat stroke, for this reason it is 
possible that the hydro electrolytic needs in children are higher than in an adult(5). 
Industrial hydration drinks (sports drinks or oral electrolytes), although they can help 
maintain water and electrolyte levels in adolescents who perform vigorous physical activities, 
have different disadvantages such as the Acidic pH and high content of added sugars that is 
closely related to the prevalence of overweight and obesity in Mexico. This has led to opt for 
alternatives in the type of beverages used by children and adolescents, considering CW an 
alternative to hydrate the pediatric population due to the chemical composition of the CW is 
currently considered a hydration option due to containing a higher average contribution of 

41 
 
K+ than conventional OE. This electrolyte is essential for the prevention and treatment of 
hypertonic or intracellular dehydration, which is more common in exercise due to high 
sweating. In which water and electrolytes are lost. The deficiency of the electrolyte K+ 
translates into muscle weakness in addition to presenting cardiac arrhythmias, for this reason, 
CW causes manifestations of hypokalemia to be less frequent and can maintain a better 
general state, in addition to its osmolality (255 and 333 mOsm/ kg of water) similar to that 
of the intestinal content (210 and 330 mOsm/kg of water) facilitates its absorption and due 
to its limited handling and its composition(53), considering that it is a better option for 
athletes for their hydration and better sports performance, without adverse effects as with 
EO, which gives rise to the research question. 
 
6.1 
Research question 
 
What is the effect of coconut water compared to conventional oral electrolytes on the state 
of hydration in adolescents who perform physical exercise belonging to the Fray Pedro de 
Gante Salesian Institute (ISFPG)? 
 
7 MATERIAL AND METHODS 
 
7.1 
Hypothesis 
 
7.1.1 Work hypothesis 
CW has a greater hydration effect than OE in adolescents who perform competitive physical 
exercise. 
7.1.2 Null hypothesis 
CW does not have a greater hydration effect than OE in adolescents who perform competitive 
physical exercise. 
 

42 
 
7.1.3 Alternate hypothesis 
EO have a greater hydration effect than CW in adolescents who perform competitive physical 
exercise. 
 
7.2 
Objectives 
 
7.2.1 General objective 
 
To determine the effect of CW vs OE on the state of hydration in adolescents who perform 
competitive physical exercise belonging to the ISFPG. 
7.2.2 Specific objectives 
• Administer CW in the experimental group and OE in the control group in adolescents 
who perform competitive physical exercise belonging to the ISFPG. 
• Determine the state of hydration using the following indicators: 
✓ To calculate the percentage of weight change through the initial weight and final 
weight in adolescents who perform competitive physical exercise belonging to 
the ISFPG. 
✓ To determine the percentage of TBW through IBE before and after physical 
exercise in adolescents belonging to the ISFPG. 
✓ To quantify and compare the USG by means of a refractometer before and after 
each training session in adolescents who perform physical exercise belonging to 
the ISFPG. 
• To compare the state of hydration between the groups that received CW vs. OE in 
adolescents who perform competitive physical exercise belonging to the ISFPG. 
• To compare the intra-group hydration status in adolescents who perform competitive 
physical exercise belonging to the ISFPG. 
 
7.3 
Trial design 
 

43 
 
The present study is presented as a Randomized Controlled Clinical Trial (RCT), double-
blind, and parallel design (Figure 5). 
 
Figure4. Parallel design of an RCT. 
Source: Lazcano-Ponce E, et al. (2004). Randomized clinical trials: variants, randomization methods, analysis, 
ethical considerations, and regulation. 
 
7.3.1 Study universe 
Adolescents from 12 to 17 years old who belong to the ISFPG and perform competitive 
aerobic physical exercise. 
 
7.3.2 Inclusion criteria 
• That the adolescent is a student belonging to the private institution ISFPG. 
• That the adolescent perform competitive physical exercise of an aerobic type (soccer, 
basketball, volleyball, cycling, among others). 
• Those students who are 12 years old and who are under 18 years old. 
• The parent or guardian of the adolescent and the student himself must agree to 
participate and comply with the autograph authorization of the informed consent 
letter. 
• The adolescent must be in good physical (Annex 2) and mental (Annex 3) health. 
 

44 
 
7.3.3 Exclusion criteria 
• Adolescents suffering from a chronic disease such as obesity, hypertension, DM, 
asthma, COPD, cancer, injuries or physical disabilities. 
• That the adolescent is allergic to any component of the treatments. 
 
7.3.4 Elimination criteria 
• Adolescents who do not complete physical training sessions. 
• That the adolescent presents a serious sports injury (fracture or sprain) during any of 
the physical exercise sessions. 
• That the adolescent decides to withdraw once the practical stage of the investigation 
has begun. 
7.4 
Operationalization of variables 
 
7.4.1 Independent Variable: Hydrating Drinks 
 
➢ 
Conceptual definition: Hydrating drinks are those intended to replenish mineral 
salts, glucose and water through hydration before, during and after intense physical 
activity(64). 
➢ 
Operational definition: AC and EO drink 
➢ 
Indicator: milliliters 
➢ 
Nature: dichotomous nominal qualitative 
 
7.4.2 Dependent variable: Hydration status 
 
➢ 
Conceptual definition: the state of water balance is called in the English literature 
the state of euhydration; the process of water loss is known as dehydration, and the 
final state of water deficit reached is called hypohydration(65). 
➢ 
Operational definition: euhydrated or dehydrated 

45 
 
➢ 
Indicator: Any 2 or more indicators (GEO, %PACT or %PP) with consistent values 
of euhydration or dehydration. 
➢ 
Nature: dichotomous nominal qualitative 
 
7.4.2.1 Urine Specific Gravity 
 
➢ Conceptual definition: Urine Specific Gravity is a practical way to measure urine, 
to associate with the state of hydration at the time of physical exercise(twenty-one). 
➢ Operational definition: Urine Specific Gravity. 
➢ Indicator: g/cm3 (Euhydrated: when GEO is less than 1,020 g/ cm3 and Dehydrated: 
when GEO is equal to or greater than 1,020 g/ cm3) 
➢ Nature: continuous quantitative. 
 
7.4.2.2 Total Body Water 
 
➢ Conceptual definition: element that represents 50-70% of the human body weight 
and comprises the two largest water compartments (intracellular (2/3) and 
extracellular water (1/3)(66). 
➢ Operational definition: percentage of total body water loss (%PACT). 
➢ Indicator: percentages (euhydrated: when the %PACT is less than 2% and 
dehydrated: when the %PACT is equal to or greater than 2%) 
➢ Nature: continuous quantitative. 
 
7.4.2.3 Body mass 
 
➢ Conceptual definition: is the measurement of body mass at two different times. 
Since 1 mL of water has a mass of 1 g, variations in body mass can be used to quantify 
water gain and loss.(31). 
➢ Operational definition: percentage weight loss (%PP). 

46 
 
➢ Indicator: Euhydrated: when the %PP is equal to or less than 0.9% and Dehydrated: 
when the %PP is equal to or greater than 1% 
➢ Nature: continuous quantitative 
 
 
 
7.4.3 Variable box 
Table14. Variable box 
INDICATORS TO MEASURE HYDRATION STATUS 
VARIABLES 
HYDRATING 
DRINKS 
HYDRATION 
STATUS 
URINE SPECIFIC 
GRAVITY 
PERCENTAGE 
OF WEIGHT 
CHANGE 
LOSS OF BODY 
WATER 
INTERRELATION 
INDEPENDENT 
DEPENDENT 
DEPENDENT 
DEPENDENT 
DEPENDENT 
CONCEPTUAL 
DEFINITION 
Drinks that, due to 
their 
composition, 
provide 
water, 
electrolytes and sugar, 
and are used above all 
by 
athletes 
or 
physically 
active 
people. 
The state of water 
balance is called in 
the 
English 
literature the state 
of euhydration; the 
process of water 
loss is known as 
dehydration, 
and 
the final state of 
water 
deficit 
reached is called 
hypohydration. 
Specific 
gravity 
measurement is a 
practical way of 
measuring urine to 
associate 
with 
hydration status at 
the time of physical 
exercise. 
It 
is 
the 
measurement 
of 
body mass at two 
different 
times. 
Since 1 mL of 
water has a mass of 
1 g, changes in 
body mass can be 
used to quantify 
water gain and loss. 
Element 
that 
represents 50-70% of 
the 
human 
body 
weight and comprises 
the two largest water 
compartments 
(intracellular (2/3) and 
extracellular 
water 
(1/3). 
OPERATIONAL 
DEFINITION 
Milliliters of AC or 
EO 
Euhydrated or 
Dehydrated 
Euhydrated or 
Dehydrated 
Euhydrated or 
Dehydrated 
Euhydrated or 
Dehydrated 
NATURE 
Qualitative 
Qualitative 
quantitative 
quantitative 
quantitative 
MEASUREMENT LEVEL 
dichotomous nominal 
dichotomous 
nominal 
Reason 
Reason 
Reason 
INDICATOR 
AC or EO 
Euhydrated: when 
any 2 indicators 
(GEO, 
%PP 
or 
%PACT) 
agree 
with 
the 
euhydration 
thresholds 
Dehydrated: When 
any 2 or more 
indicators 
(GEO, 
%PP or %PACT) 
are consistent with 
Euhydrated: when 
the GEO is ≤ 1,020 
g/cm³ 
Dehydrated: when 
the GEO is > 1,020 
g/cm³ 
Euhydrated: when 
the %PP is equal to 
or less than 1% 
Dehydrated: when 
the %PP is greater 
than 1% 
Euhydrated: when the 
%PACT is less than 
2%. 
Dehydrated: when the 
%PACT is equal to or 
greater than 2%. 

47 
 
the 
dehydration 
values. 
STATISTICAL TEST 
X²or Fisher's test 
X²or Fisher's test 
X²or Fisher's test 
X²or Fisher's test 
X²or Fisher's test 
Font: 
7.5 Sample size 
For the sample size, the sample calculation formula was used to test hypotheses in studies 
that compare two means(67): 
𝒏= 𝟐[
(𝒁𝜶 +  𝒁𝜷)𝝈
𝑿𝟏−𝑿𝟐
]𝟐 
The formula was made with a confidence level of 95% (1.96) and a beta error of 95% (1.28), 
in addition, to clear the formula, 2 articles based on adults who administered AC were used 
(Saat M, et al 2012 and Peart J, et al., 2016) since there are no studies in which AC has been 
administered to adolescent athletes or those who perform physical exercise. The first study 
administered a mean of 1875 ml of AC and the second study 1420 ml of AC. A Standard 
Deviation (SD) of 412 ml was used. The formula was replaced, which yielded a result of 17 
subjects, of which a loss of 30% was taken into account, that is, 22 adolescents per group, 5 
participants per group could not participate, so a total of 17 adolescents per group were 
evaluated. 
 
 𝒏= 𝟐[
(𝟏.𝟗𝟔 + 𝟎.𝟖𝟒)𝟒𝟏𝟐
𝟏𝟖𝟕𝟓−𝟏𝟒𝟐𝟎
]² = 17.2 17 + 30%= 22 per group 
 
7.6 Randomization 
The primary purpose of randomization was to ensure that the possible causal inference 
observed at the end of the study was not due to other factors. The balanced block method was 
used based on the assigned treatment (A or B) as shown in figure 6. This method consisted 
of assembling a series of blocks, formed by a certain number of cells, in which the different 
types of treatment. The number of blocks was determined by the number of participants to 
include and the number of cells that it was decided to include in each block. Each block had 

48 
 
in each cell one of the treatment alternatives and within each block there was a balanced 
number of possible treatments. 
 
 
Figure5. Randomization using the balanced block method. 
Source: Lazcano-Ponce E, et al. (2004). Randomized clinical trials: variants, randomization methods, 
analysis, ethical considerations, and regulation. 
 
 
7.7 
Masking or blinding 
 
For the present investigation, a double blind was used, which consists first of blinding the 
study subjects so that they do not know the type of treatment they are receiving (AC or EO), 
so it was considered that the EOs used in the study were flavored. To coconut so that both 
treatments had similar flavors, and that they had the same color appearance. The researcher 
was blinded with the help of a person external to the study who was in charge of labeling the 
treatment containers, which were letters A and B, without specifying the type of treatment 
(AC or EO). 
 
7.8 
Interventions 
 
34 healthy adolescents between 12 and 17 years old were selected through simple sampling 
and the treatment they received was randomly assigned, whose treatment was the same 

49 
 
during the 4 sessions of physical exercise, which lasted 60 ± 10 min. approximately per 
session, whose characteristics of the exercise per session are described later. 
7.8.1 Flowchart 
 
 
 
Figure6. Flowchart of the progress of the phases of a parallel RCT of two groups. 
Source: CONSORT (2010) 
 
 
7.8.2 Execution protocol taking into account the epidemiological situation of CoVid-
19 
1. Due to current epidemiological reasons of CoVid-19, the subjects were divided into 
two groups of 17 subjects, this in order to reduce population and risk of contagion, 
following the health protocols established by the institution mentioned in Annex 4. 
They were summoned at 12:00 pm on Mondays or Tuesdays only according to the 
group assigned to start with the collection of personal data (Annex 5) and a mental 
test called Psychological Characteristics related to Sports Performance (CPRD) 
(Annex 6) whose test was applied by an expert in the area of psychology. 

50 
 
2. After taking personal data, hydrating drinks were immediately administered before 
training (6 ml x kg of weight) 4 hours before. At 2:00 p.m., the corresponding 
hydrating drink (4 ml x kg of weight) was administered again. Each study participant 
was provided with a 1000 ml graduated glass given by the researcher to keep track of 
the drink administered at the different times of each session. 
3. Then, a 200 ml dose of hydrating drink was administered immediately before exercise 
(10-15) min, and anthropometry and urine samples were taken just before exercise to 
ensure a state of euhydration. To record body mass, the protocol developed by the 
International Society for the Advancement of Kinanthropometry (ISAK) (Annex 7) 
was followed.(68). The study subjects were weighed in sports shorts and barefoot 
before starting the physical exercise, having been instructed that, in the case of 
urinating or defecating, they should do so before the initial weighing. Simultaneously 
with taking the body mass, the % of ACT was determined by electrical bioimpedance. 
For the recording of body mass and % of water ACT, the Tanita BC-533 
bioimpedance scale was used with a reliability of 97%, precision of 0.1kg and with a 
measurement range of 0-150kg. 
4. Urine was analyzed immediately (less than 30 min at room temperature) using a 
manual refractometer by nutrition students previously trained in the care and analysis 
of urine samples. 
5. The physical exercise protocol was continued, receiving one session per week with a 
duration of 60 ± 10 min each session for 4 sessions. The exercise sessions were carried 
out in the Domingo Savio sports fields and were taught under the charge of the main 
researcher who has worked as a sports coach in the soccer area for 4 years, in addition 
to being trained for this purpose in the same institution in which the study will be 
carried out. Days prior to the start of the practical execution of the protocol, parents 
and selected students were summoned virtually to a meeting where the dynamics of 
the research were widely explained. The physical exercise sessions consisted of 4 
parts: 
a. The first part of the 10-minute warm-up and stretching workout to increase 
your baseline HR and prepare the body for the next high-intensity stages and 

51 
 
prevent injury in teens. The heating had a rest of 5 minutes and hydration of 
2 ml x kg of weight. 
b. This second part was developed in 12 min of continuous jogging around the 
field at a medium pace with the objective of going around the soccer field 
every 1 minute 36 seconds, giving a total of 7 and a half laps (Cooper test). 8 
min of rest for the total recovery of energy systems and hydration of 2 ml x 
kg of weight. 
c. In the third part of the training, the adolescents ran from one line to another, 
twenty meters apart, at the rhythm of a tape recorder. This race pace will 
increase every minute. Subjects began the test at a speed of 8 km/hr, the first 
minute they increased to 9 km/hr, and each minute thereafter they increased 
the pace by ½ km/hr. The test ended in approximately 10 min and there was 
a rest of 8 min and hydration of 2 ml x kg of weight. 
d. In the last part of the training session, it was a type of exercise based on 
Tabatha, which consisted of performing 8 different exercises for 20 seconds 
with a 10-second rest to the rhythm of the marked music, giving a time of 4 
minutes per Tabatha. . Two Tabatha’s were made with an intermediate rest of 
3 min between each Tabatha and hydration of 2 ml x kg of weight. 
6. At the end of this last stage of the training session, anthropometry was taken and 
information was collected where the percentage of weight change, ACT by 
bioimpedance and GEO were determined immediately to avoid bias of the samples at 
room temperature before to begin the final hydration, since, if it had been done in 
reverse, it was very likely that no one would come out in a dehydrated state. After the 
anthropometry, they were administered the corresponding post-exercise hydration 
(1.5 ml x kg of weight). The calculation of the percentage of lost weight will be 
calculated using the following formula: % Lost Weight or Dehydration = [(Initial 
weight - Final weight) / Initial weight] x 100. 
 
 
 

52 
 
7.8.3 Hydrating drinks 
 
Previously it was mentioned that hydration must be according to the weight of the study 
subject, so following the personalized hydration guidelines, a format was created in the Excel 
program where the milliliters to be consumed by each subject were automatically calculated 
and a person in charge was placed in beverage containers serving the right amount, not too 
much or too little. 
• 4 hours before: 7 ml x kg of weight 
• 2 hours before: 4 ml x kg of weight 
• Immediately before: 200 ml 
• During (4 breaks): 2 ml x kg of weight 
• Post-exercise: After the exercise, once the MC, ACT and GEO measurements were 
taken, 1.5 ml/kg of weight were administered to recover weight and lost water. 
Among the aspects that were also taken into account for adequate hydration in adolescents, 
apart from the guidelines and recommendations for fluid intake in both quantity and 
distribution mentioned above, CHO concentrations (5-8%) at temperature (8 -10 ºC), and the 
taste of the drink. Electrolit® coconut flavor was used as the sports drink to be administered, 
whose nutritional composition is described in Table 18. 
Table15. Nutritional composition of the sports drink that will be used in the project 
(Electrolit®). 
Component 
Content in 100 ml of formula 
Sodium chloride 
12mg 
Potassium chloride 
149mg 
Calcium chloride dihydrate 
30mg 
Magnesium chloride hexahydrate 
41mg 
sodium lactate 
314mg 
Glucose 
5mg 
%HCO 
5% 
Source: Electrolit® 

53 
 
 
Hydrating drinks were administered under the same conditions and temperature as mentioned 
above. The drinks were poured by the person in charge of the masking into two 19-liter 
thermos coolers with a dispenser, of the igloo® brand, labeled with the type of treatment 
assigned. 
 
7.8.4 Meal plan 
 
We stablished a feeding plan which was standardized and carried out by the LN Alexis Adan 
Lopez Maria (investigator of the present study). To standardize the food plan, the general 
needs of the age group and the average age, weight and height of the participants were taken 
into account, using the Harris Benedict formula as a predictive equation, since in a study 
carried out in 2015 by Becerril Marlu, this formula was the closest to the average measured 
resting energy expenditure, with a difference of 12.1 kcal/day in Mexican children(69).How 
I mentioned previously eating and hydration habits is a factor in altering the state of 
hydration, so the meal plan indicated had the purpose of eliminating the bias that the different 
eating habits in each subject could intervene, in addition about what It was not necessary to 
keep track of the intake of water ingested in the foods and the quantity of liquids in each 
individual, since the hydration guidelines considering the time, quantity and type of drink 4 
hours before the physical test ensured the state of euhydration in the study subjects. 
 
7.9 Methods and statistical analysis 
1. The Shapiro Wilk test (small samples <50) was applied to determine the distribution 
of the data, which showed an asymmetric distribution with a positive bias in the age 
of the subjects. 
2. For descriptive statistics, qualitative variables were presented as numbers, 
percentages (%), frequencies, or interquartile ranges, as the case may be, and 
quantitative variables were expressed as mean (X), ± standard deviation (SD). 
3. Student's t-test was used to compare the pre- and post-exercise hydration indicators 
in general and by treatment received (CW and OE). 

54 
 
4. Regarding inferential statistics, the statistical significance test was performed to 
compare two independent qualitative means (CW and OE) using X2. 
5. Fisher's exact test was used in exercise sessions with frequencies less than 5 in any 
cell. 
6. The analysis of relative risk (RR), absolute risk (AR), relative risk reduction (RRR), 
absolute risk reduction (ARR) and the number needed to treat (NNT) was performed. 
Calculation of the aforementioned analyzes helped us determine the clinical 
significance of the study results. 
7. For the contrast of the means of the independent variables on the different mean of 
the dependent variable, the X2 test was carried out. 
8. A 95% confidence interval (CI) with a standard error of ± 1.96 was used. 
9. Statistical significance was established when p ≤ 0.05. 
 
8 ETHICAL ASPECTS 
 
The present study adheres to the guidelines of the Declaration of Helsinki and respect for the 
principles of beneficence, non-maleficence, justice and autonomy of decision. (Ethical 
Principles for Medical Research Involving Human Subjects 64th version, October 2013). In 
addition, in accordance with the General Health Law on Health Research Title II, Chapter I, 
Articles 17. III (1997), the present study is classified as greater than minimum risk in those 
that use: radiological studies and with microwaves, trials with medications and modalities 
defined in article 65 of the regulation, trials with new devices, studies that include surgical 
procedures, extraction of blood greater than 2% of the circulating volume in neonates, 
amniocentesis and other invasive techniques or procedures greater, those that use random 
methods of assignment to therapeutic schemes and those that have placebo control, among 
others. The signing of a letter of informed consent in writing will be requested from the 
institutional director to carry out the study in the academic institution (Annex 8) by means of 
a letter issued by the coordination of the postgraduate degree in medical sciences and by the 
advisor in charge. Of the study (Annex 9). Parents or guardians will also be asked to sign the 
informed consent letter (Annex 10) as well as the study subjects' informed assent letter 

55 
 
(Annex 11). Likewise, the anonymity of the study subjects is taken care of, clarifying to the 
parents of the minors that the data obtained is only for research purposes. 
The Research Ethics Committee may waive compliance with these requirements for justified 
reasons. Article amended DOF 04-02-2014. This study was submitted for evaluation to the 
Research Ethics Committee of the State Institute of Cancerology, whose verdict was 
approving under registration CEICCI06082021-AGCOHID-12 and the letter is shown 
attached in Annex 12. The same project continues in the registration process in the clinical 
trials. 
 
9 RESULTS 
 
34 male adolescent subjects with an age range of 12 to 17 years were recruited and analyzed, 
whose characteristics of age, weight, height and BMI are described in Table 19. The study 
subjects were selected and assigned to a drinking treatment at random by means of the 
balanced block method. The experimental protocol consisted of 4 hydrated training sessions 
4 hours before training (345.03 ± 74.51 ml), 2 hours before (230.02 ± 49.67 ml) and 
immediately before starting the dehydration process (200.00 ± 0.00 ml) which had a duration 
of 65 min ± 5 min. During the exercise, the subjects were hydrated on 3 occasions (every 20 
min) where the treatment corresponding to each individual was administered (115.01 ± 24. 
 
Table16. Description of the study population. 
 
Half 
Dev. half 
Asymmetry 
AGE (YEARS) 
13.03 
1,087 
1,444 
WEIGHT (KG) 
57.50 
12.41 
.507 
SIZE (CM) 
162.50 
10,936 
.320 
BMI 
21.58 
3.03 
.605 
The asymmetry statistic indicates a positive bias in the variables as they are greater than 0, with a greater bias 
in the age of the subjects. 
 
 

56 
 
9.1 Description of the subjects prior to the exercise sessions 
 
The 34 subjects presented to each training session in a euhydrated state with an average initial 
weight of 56.74 ± 13.32kg, USG of 1.028 ± 0.011 g/cm3 and TBW of 68.47 ± 5.40%. At the 
end of the 4 sessions, the subjects had the following data on average: final weight of 56.24 ± 
13.14 kg, USGf of 1.032 ± 0.012 g/cm3 and TBWf of 68.37 ± 5.22%, which indicates that 
the subjects had a weight loss average of 0.50 ± 0.19 kg, USGf of 0.004 ± 0.001 g/cm3 and 
TBWf of 0.11 ± 0.19%. Table 20 breaks down the results obtained before and after the 
physical test of the hydration status indicators, and Table 21 shows the differences obtained 
between these indicators with their significance. 
Table twenty. Description of the initial and final hydration status according to the indicators 
evaluated per session. 
 
Body mass (kg) 
USG (g/cm3) 
%TBW 
 
Pre 
post 
Pre 
post 
Pre 
post 
Session 1 
56.61 ± 
13.33 
56.35 ± 
13.27 
1.027 ± 
0.011 
1.035 ± 
0.011 
69.59 ± 
5.170 
68.76 ± 
5.270 
Session 2 
56.75 ± 
13.26 
55.95 ± 
12.90 
1.030 ± 
0.012 
1.035 ± 
0.013 
67.36 ± 
05.35 
67.13 ± 
05.56 
Session 3 
56.59 ± 
13.12 
56.06 ± 
13.01 
1.029 ± 
0.011 
1.034 ± 
0.011 
68.09 ± 
6.431 
68.72 ± 
5.253 
Session 4 
57.03 ± 
13.60 
56.61 ± 
13.38 
1.026 ± 
0.012 
1.029 ± 
0.012 
68.86 ± 
4.679 
68.86 ± 
4.782 
USG= Urine Specific Gravity. TBW= Total Body Water. Data is presented as mean± SD. 
 
Table twenty. T test for pre and post comparison in indicators of hydration status 
Indicator 
Half 
OF 
Significance 
Pesoi - Pesof 
0.50 ± 0.23 
.021 
ACTi - ACTf 
0.10±0.60 
.749 
GEOi - GEOf 
0.005±0.002 
.015 
 
Next, the comparisons of the hydration indicators before and after physical exercise are 
shown, separated by intervention groups (CW and OE) in tables 22 and 23. The indicators 

57 
 
show a better trend of hydration in the pre and post exercise values. With AC than with OE, 
although with no significant difference between sessions. 
Table17. Comparison of pre and post hydration indicators in the CW group 
 
Body mass (kg) 
GEO (g/cm3) 
%ACT 
 
Pre 
post 
Pre 
post 
Pre 
post 
Session 1 
53.38 ± 
10.93 
53.25 ± 
10.74 
1.023 ± 
0.009 
1.032 ± 
0.011 
69.62 ± 
4.529 
68.95 ± 
4.370 
Session 2 
53.74 ± 
11.69 
53.09 ± 
11.47 
1.028 ± 
0.012 
1.032 ± 
0.015 
68.69±5,7
11 
68.53 ± 
5.626 
Session 3 
52.80 ± 
10.80 
52.25 ± 
10.67 
1.027 ± 
0.013 
1.033 ± 
0.011 
68.40 ± 
7.934 
69.42±5,7
82 
Session 4 
53.58 ± 
11.53 
53.39 ± 
11.54 
1.022 ± 
0.012 
1.025 ± 
0.012 
69.86 ± 
4.297 
70.28 ± 
3.531 
GEO= Urine Specific Gravity. ACT= Total Body Water. It is observed that in session 3 and 4 there was a gain 
in %ACT, although not in body mass, on the contrary, it is shown that in all sessions the subjects showed a pre-
exercise GEO greater than 1,020 and less than 1,030 g/ cm3 classified as mild to moderate dehydration. 
Table18. Comparison of pre and post hydration indicators in the OE group 
 
Body mass (kg) 
GEO (g/cm3) 
%ACT 
 
Pre 
post 
Pre 
post 
Pre 
post 
Session 1 
59.85 ± 
14.99 
59.46 ± 
15.07 
1.032 ± 
0.011 
1.039 ± 
0.009 
69.56 ± 
5.876 
68.57 ± 
6.175 
Session 2 
59.76 ± 
14.38 
58.81 ± 
13.93 
1.033 ± 
0.011 
1.038 ± 
0.011 
66.04 ± 
4.775 
65.74 ± 
5.289 
Session 3 
60.39 ± 
14.42 
59.88 ± 
14.29 
1.032 ± 
0.009 
1.036 ± 
0.010 
67.79 ± 
4.706 
67.83 ± 
4.668 
Session 4 
60.47 ± 
14.94 
59.82 ± 
14.64 
1.029 ± 
0.011 
1.034 ± 
0.010 
67.85 ± 
4.954 
67.44 ± 
5.514 
GEO= Urine Specific Gravity. ACT= Total Body Water. We can observe that in session 3 there was a slight 
gain in %ACT, on the other hand, the GEO pre-exercise shows that in most sessions the subjects showed a 
value greater than 1,030 g/cm3, which is classified as severe dehydration. 
Table 24 shows the frequency of the hydration status of the subjects post-exercise during the 
4 training sessions that the study lasted. 
Table19. General cross table of the state of hydration with respect to the assigned treatment. 
 
Hydration Status 
Total 
Euhydrated 
Dehydrated 
Tx 
Assigned 
AC 
not observed 
53 
15 
68 
EO 
not observed 
36 
32 
68 
Total 
not observed 
89 
47 
136 
 
 

58 
 
9.2 RR, RRR and NNT tests 
 
The absolute risk (AR), the relative risk (RR), the absolute risk reduction (ARR), the relative 
risk reduction (RRR) and the number needed to treat (NNT) were estimated, whose values 
are shown in Table 25. And they indicate that the probability of having the dehydration event 
with any treatment was 35% as well as the probability of ending the sessions dehydrated in 
47% when receiving the OE treatment. The ARR indicates a 25% reduction in dehydration 
in subjects treated with AC compared to those who received EO. Finally, the NNT throughout 
the study shows that 4 subjects needed to be treated to obtain 1 euhydration effect after 
physical exercise treated with AC. 
 
Table20. Estimation of RA, RR, RAR, NNT and RRR 
AR 
0.35 
RR 
0.47 
RAR 
0.25 
RRR 
0.53 
NNT 
4 
Clinical data show a favorable trend for AC hydration to prevent dehydration and its adverse effects. 
 
 
 
9.3 Frequency of hydration status per exercise session 
 
Table 26 shows the frequencies of hydration status broken down by exercise sessions and 
according to the assigned treatment. 
 
Table21. General table of sessions regarding treatment and hydration status 
Hydration 
Status 
Treatment 
Physical exercise sessions 
Session 1 
Session 2 
Session 3 
Session 4* 
Total 
AC 
68 
Euhydrated 
 
12 
12 
13 
16 
53 
Dehydrated 
5 
5 
4 
1 
15 

59 
 
EO 
68 
Euhydrated 
 
8 
7 
13 
8 
36 
Dehydrated 
9 
10 
4 
9 
32 
During the first 3 sessions, no significant difference in hydration is seen between AC and EO; however, a greater 
trend of hydration is shown with AC, being significantly higher in the last session of the study. 
*Session with statistical significance between treatments. 
 
 
9.4 Comparison between groups using Chi square test 
The chi-square test was performed for each of the sessions, accepting H0 in the first 3 
sessions and accepting H1 in the last session. The p obtained in table 27 are shown below. 
Fisher's exact test, alternative to the Chi square test, was used in the last session because a 
frequency of less than 5 was obtained in one of the boxes of the cross table. 
 
Table22. Chi square broken down by sessions 
 
Significance 
Session 1 
Significance 
Session 2 
Significance 
Session 3 
Significance 
Session 4 
Pearson chi-
square 
0.163 
0.084 
1,000 
0.003* 
Continuity 
Correction 
0.296 
0.167 
1,000 
0.008 
Fisher 
exact 
test 
- 
- 
- 
0.007* 
likelihood 
ratio 
0.161 
0.082 
1,000 
0.001 
*P<0.05 showing statistical significance between treatments. 
-Does not apply 
 
9.5 Intragroup comparison in the different sessions 
To find out the variations in the frequencies of a single treatment in the 4 different exercise 
sessions, Cochran's Q was performed in each study group. In treatment group A (CW), the 
frequencies of hydration between sessions did not show significant differences with a value 
of Q= 3.909 and p>0.005. 
 

60 
 
With relation to treatment B (EO) a greater variation of the frequencies in the state of 
hydration was observed, obtaining a Q=5.739, however, there were no significant differences 
in the treatment in each of the sessions (p>0.05). 
 
10 DISCUSSION 
 
Coconut water has been widely studied for its antimicrobial properties, for its uses in the 
culinary field and the benefits it offers as a natural drink for athletes. Dehydration is a very 
common problem in both athletes and the general population, and a low level of hydration 
can affect physical and mental health. In the pediatric population there is a risk of heat stroke 
due to their low sweating rate and thermoregulation capacity, so the present study aimed to 
compare the effect of AC vs EO (Electrolit®) on hydration status in adolescents who perform 
physical exercise. 
There are few studies that compare coconut water on hydration levels in adolescent athletes, 
so the characteristics of the populations in different studies found are compared below, but 
with similar objectives in people who perform physical exercise (soccer, treadmill, cycling, 
volleyball, etc.). Previous studies such as: Daniel J. Peart, et al 2016; Kalman, et al. 2012; 
Saat M, et al. 2002 and Pérez and Aragón 2011, evaluated trained adults with samples of less 
than 12 participants. On the other hand, this study recruited 34 subjects from the pediatric 
population (adolescents) aged 13.03 ± 1.09 years with different physiological characteristics 
that can contribute to providing new knowledge that can be used in later studies. Added to 
this, 
Going back to the 4 studies mentioned above, all carried out physical exercise of 
approximately 60 min comparing 3 or 4 hydrating drinks (natural coconut water, bottled 
coconut water, simple bottled water and/or sports drink) using in some of them bottled 
coconut, knowing that bottled products are added with sugars and preservatives to prolong 
the shelf life of the product and may further affect the health of athletes. In the present study, 
natural or plain water was not compared with the other hydrating drinks since it was 
considered unnecessary to include it due to its electrolyte deficit, which makes it a drink not 

61 
 
suitable for sports since, when consumed and does not contain electrolytes, plain water 
dilutes the few remaining electrolyte concentrations in the blood, 
Among the similarities found was that no study mentioned above found significant 
differences between the drinks compared. Saat M, et al, 2002 performed only one exercise 
session, which does not allow the study to find significant differences compared to the other 
studies that, unlike this one, performed 3, 4 and 3 sessions in the studies by Daniel J Peart, et 
al 2016; Kalman, et al 2012 and Pérez and Aragón 2011 respectively. In the present study, 4 
sessions of physical exercise with a duration similar to 60 ± 10 min were carried out, as in 
the study carried out by Kalman, et al 2012, where the previously presented results show a 
trend of greater hydration with AC in each session. Without being statistically significant 
during the first 3 sessions (p>0. 
An important part in the comparative studies are the techniques and instruments for 
evaluating hydration, since they vary greatly in their applicability due to methodological 
limitations such as the circumstances necessary for measurement such as reliability, ease of 
application and cost (simplicity), sensitivity to detect small but significant changes in 
hydration status (precision). In all the studies, indirect methods were used that were the same 
or similar in the present study, with body mass and USG being one of the most used methods 
due to their practicality in the field of clinical research; on the other hand, the gold standard 
was not included. In no study since it includes, in addition to blood osmolality, the isotopic 
dilution for TBW and they are mostly invasive methods, 
 
10.1 Limitations 
There were some limitations in the study of intervening variables that could affect hydration 
levels and that, for financial reasons or external to the researchers in charge, could not be 
controlled or included in the study. In this case, the climate was an environmental factor that 
could not be controlled due to the facilities where the study was carried out. Another factor 
was that the gold standard of hydration was not applied for reasons of practicality and 
finances, in addition, hydration levels change in a matter of minutes and waiting for 
anthropometric and urine measurements could have been an intervening factor. 

62 
 
On the other hand, the acceptance of beverages was something that was not contemplated 
since the participating adolescents did not have a hydration habit with CW or OE coconut 
flavor, and there were even subjects who had tried the assigned hydrating drink for the first 
time. 
 
11 CONCLUSION 
CW and OE have the same effect on hydration levels in adolescents who perform physical 
exercise, however, a significant difference was found in the last session, the effect being 
greater with CW compared to OE. 
 
12 PERSPECTIVES 
Session 4 of this study with significant results may give rise to future research on AC due to 
the trend shown for euhydration in each session. 
Prolonging the number of sessions can show greater significant results due to the 
physiological adaptation to exercise and acceptance of AC in the body. 
Applying the gold standard in conjunction with the methods used in the present study can 
give a more accurate diagnosis of hydration status. 
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39. Chevront SN. EVALUATION OF HYDRATION IN ATHLETES. 2005;18(2):8. 
40. Captain Jimenez C, Aragon-Vargas LF. Simple method to check euhydration. Think 
About Mov Rev Cienc Exercise Health. 2010 Aug 5;7(1):23-31. 
41. Azúcar P.M, Cano Sch. F, Marín B. V, DÃ\-az B. E, Salazar R. G, Vásquez FL 
Estimation of total body water by deuterium in pediatric peritoneal dialysis. Rev Chile 
Pediatrics. 2003; 74:504-10. 

66 
 
42. García F, Mas M. Updates in the study and management of hyponatremia. medigraphic. 
2007;23(2):138-40. 
43. Flasar C. What is the specific gravity of urine? Nurs Ed Esp. 2009 Aug;27(7):52. 
44. Lozano Triana CJ. General urine test: a useful test in children. Rev Fac Med. 2016 Mar 
30;64(1):137-47. 
45. Alvero-Cruz JR, Correas Gómez L, Ronconi M, Fernández Vázquez R, Porta i 
Manzañido J. Electrical bioimpedance as a method for estimating body composition, 
practical rules for its use. Rev Andal Med Sport. 2011;4(4):167-74. 
46. Cirigliano H. Hydration and physical activity. FREE AIR [Internet]. Jan 16, 2018;46. 
Available at: https://www.revista-airelibre.com/2018/01/16/hidratacion-activity-fisica/ 
47. Eugenio Luna P. Sport and ergonomics: a view from bioethics. Rev Medical Clinic Las 
Condes. 2012 May;23(3):349-54. 
48. Páez J. Hydrating Drinks. The 
PROFECO laboratory 
informs [Internet]. 
DOCPLAYER. 
2018. 
Available 
at: 
https://docplayer.es/80351963-Bebidas-
hidratantes-el-laboratorio-profeco-informa.html 
49. Lisett Hernandez Ponce, MonicaSuheily Carrasco García, Trinidad Lorena Fernández 
Cortés, Marco Aurelio González Unzaga, Araceli Ortiz Polo. Nutrition and hydration 
in the athlete, its impact on sports performance. Health Educ Scientific Bol Inst Cienc 
Salud Autonomous Univ. Hidalgo State. 2021 Jun 5 [cited 2022 Mar 12];9(18). 
50. Rodríguez Carranza R. Academic Vademecum of Medications. 6th edition. Mexico, 
DF: McGraw-Hill; 2013. 
51. Ministry of Health. Oral Rehydration Solution (electrolytes). Lima Perú; 2010 Mar. 
Report No: 03-2010. 
52. Sánchez-Valero L, Matallana MC. Isotonic drinks for athletes and theirhealth 
involvement. [Internet] [End-of-degree project]. [Madrid, Spain]: Complutense 
University of Madrid; 2017. Available at: https://eprints.ucm.es/id/eprint/57012/ 
53. Espinosa F, Olivares C. The power of... 100% natural coconut water [Internet]. The 
power 
of 
the 
consumer. 
2016. 
Available 
at: 
https://elpoderdelconsumidor.org/2016/07/el-poder-de-el-agua-de-coco-100-
natural/#:~:text=Al%20ser%20un%20excelente%20hidratante 
,to%20prevent%20heart%20diseases%20C3%B3n. 
54. Piaggio LR. Sugary drinks and sponsorship of sporting events. The right to health of 
children and adolescents at stake. Arch Argent Pediatr. 2019 Feb 1 [cited 2021 Mar 
2];117(1). 

67 
 
55. Science A. Coconut cultivation [Internet]. infoAgro.com. s/f. Available at: 
https://www.infoagro.com/frutas/frutas_tropicales/coco.htm 
56. Perez NGU. Consumption preferences for products derived from coconut in the 
Yucatan Peninsula, Mexico* Consumption preferences for products derived from 
coconut in Yucatan Peninsula, Mexico. :13. 
57. Yong JW, Ge L, Ng YF, Tan SN. The Chemical Composition and Biological Properties 
of Coconut (Cocos nucifera L.) Water. Molecules. 2009 Dec 9;14(12):5144-64. 
58. PO Nitrogen and potassium fertilization of the coconut palm in Colima. Terra 
Latinoam.2003; 21:401-8. 
59. Carvajal CC. Coconut water: An alternative solution in oral rehydration therapy. Rev 
Mex Pediatr. 2003; 70(3):118-22. 
60. Segura-Badilla O, Lazcano-Hernández M, Kammar-García A, Vera-López O, Aguilar-
Alonso P, Ramírez-Calixto J, et al. Use of coconut water (Cocus nucifera L) for the 
development of a symbiotic functional drink. Heliyon. March 2020; 6(3): e03653. 
61. Castro-Sepúlveda M, Astudillo S, Álvarez C, Zapata-Lamana R, Zbinden-Foncea H, 
Ramírez-Campillo R, et al. Prevalence of dehydration in Chilean professional soccer 
players before training. Nutr Hosp. 2015; 32:308-11. 
62. Saat M, Singh R, Sirisinghe RG, Nawawi M. Rehydration after Exercise with Fresh 
Young Coconut Water, Carbohydrate-Electrolyte Beverage and Plain Water. J Physiol 
Anthropol Appl Human Sci. 2002;21(2):93-104. 
63. Peart DJ, Hensby A, Shaw MP. Coconut Water Does Not Improve Markers of 
Hydration During Sub-Maximal Exercise and Performance in a Subsequent Time Trial 
Compared to Water Alone. Wilderness Environ Med. 2013 Mar;24(1):78-9. 
64. Scaccia C. Isotonic drinks. Association of Health and Food Professionals [Internet]. 
May 15, 2017; Available at: http://apsal.org/bebidas-isotonicas/ 
65. Caldas R. HYDRATION STATUS AND PHYSICAL WORK CAPACITY.Physical 
education and sport. 1996;18(2):17. 
66. Navarra University Clinic. Total body water. In: Medical dictionary [Internet]. Madrid 
Spain; 2020. Available at: https://www.cun.es/dictionario-medico 
67. AS Formulas for calculating the sample in health research. Health in Tabasco.2005; 
11:333-8. 
68. Hansde-Ridder J. International Society for the Advancement of Kinanthropometry. 
International Society for the Advancement of Kinanthropometry; 2001. 

68 
 
69. Calf-Sánchez ME, Flores-Reyes M, Ramos-Ibáñez N, Ortiz-Hernández L. Equations 
for predicting resting energy expenditure in schoolchildren from Mexico City. Mexico 
Pediatric Act. 2015; 36:147-57. 
70. A. AI, G. MP, CJ Multivariate analysis of the psychological profile of college athletes. 
Application of the CPRD in Mexico. Science Physical Educ.2015; 17:1-11. 
 
 
14 ANNEXES 
 
14.1.1 Annex 1: Urine collection technique, conservation and analysis. 
It is necessary to process the sample in the clinical laboratory as soon as possible. If the 
sample cannot be analyzed within the first 30 minutes of collection, it should be refrigerated 
in the refrigerator door at 4 degrees Celsius for a maximum of 24 hours. hours, otherwise 
there is a risk that the substances contained in it will be altered due to the effects of ambient 
temperature and sunlight after 2 hours of collecting the sample(44). For a regular urinalysis 
with urine specific gravity, about 20 ml should be collected. Urine specific gravity can be 
tested with one of these methods: hydrometer or urinometer, a multi-test dipstick, and by 
means of a refractometer or total solids meter. This last method is the most reliable and the 
measurement technique is as follows: place a drop of urine on the glass of the urinometer and 
put another glass on top. The path of light bends (as it passes through the sample and gives 
the refractive index, that is, the ratio between the speed of light in air and the speed of light 
in the sample. The degree of refraction is directly proportional to urine density(43). 
 
14.1.2 Annex 2: Aspects to be evaluated to measure physical health as an inclusion 
criterion. 
A. BMI will be evaluated in order not to include subjects with obesity that may affect 
exercise performance and the percentage of total body water in the body. 
B. The physical examination will determine through observation conditions that make it 
impossible to perform physical exercise (lack of some limbs). 

69 
 
14.1.3 Annex 3: Criteria for measuring mental health in sports performance. 
Athletes can be classified in any of the following risk profiles, if their scores are below the 
25th percentile on the scales marked in the results table shown in Annex 6. The authors 
indicate profile one as the maximum risk profile. And the lowest risk number seven. 
Risk profile: 
1. Scores are below the 25th percentile in Stress Management, Influence of Performance 
Evaluation, and Motivation. 
2. Scores are below the 25th percentile on the Stress Control and Influence of 
Performance Assessment. 
3. Scores are below the 25th percentile in Stress Management and Motivation. 
4. Scores are below the 25th percentile on Influence of Performance and Motivation 
Assessment. 
5. Scores are below the 25th percentile in Stress Management and Mental Ability. 
6. Scores are below the 25th percentile on Motivation. 
7. Scores are below the 25th percentile in Team Cohesion(70). 
 
14.1.4 Annex 4: Health protocol to be followed by the educational institution. 
 
1. Only teachers, students and study managers will be allowed to enter the sports 
facilities. 
2. Access to the facilities must be mandatory with a face mask wearing it correctly 
(covering the nose and mouth). 
3. The body temperature of everyone entering the facility will be recorded. 
4. Once the temperature is registered and it is optimal, it will be atomized with sanitizer 
and anti-material gel will be put on them. 
5. Within the facilities, the healthy distance between students and educational staff will 
be kept. 
6. The sports material to be used will be disinfected before and after each training 
session. 

70 
 
7. A disinfected glass will be given to each study subject that will bear their name in 
order not to confuse glasses. 
8. Any student with signs or symptoms of COVID will be denied entry and therefore 
excluded from the study. 
 
14.1.5 Annex 5: Personal information collection sheet for each subject. 
 
14.1.6 Annex 6: CPRD Test 
 
Dear athlete: 
Amateur or professional competitive sport requires, increasingly, that the training and 
preparation methods of athletes whose objective is to achieve success at the highest level, 
evolve taking into account the physical, technical and psychological characteristics of the 
athletes who they must be trained, as well as their opinion regarding issues related to their 
participation in tests, matches and competitions. For this reason we are writing to you as we 
believe that, as a competitive athlete, your answers will be of great help to us. Specifically, 
it is about knowing certain characteristics and opinions of adolescent athletes belonging to 
the ISFPG in relation to their participation in sports training and competitions. To this end, 
we would be grateful if you would answer the questions attached. There are no right or wrong 
answers, each athlete is different, which is why we ask you to answer with the utmost 

71 
 
sincerity. The questionnaire is strictly confidential; if he wants to put his name he can do it 
and in that case we will be able to inform you about his answers later. If you do not want to 
put your name, you can leave the corresponding space blank. We look forward to your 
valuable and kind cooperation. If you do not want to put your name, you can leave the 
corresponding space blank. We look forward to your valuable and kind cooperation. If you 
do not want to put your name, you can leave the corresponding space blank. We look forward 
to your valuable and kind cooperation. 
Thank you very much. 
*INSTRUCTIONS: 
Please respond to each of the following statements indicating how much you agree or 
disagree with the statements in question. 
In each sentence, 6 response options are shown, represented by a circle. Fill in the circle that 
you choose according to the position of agreement or disagreement with the sentence. If you 
do not understand a sentence, please fill in the circle in the last column. 
 
 
 
Date: 
Colima, Col. On __________ of the month of _______________________ 
year_________ 
 
Surname name: __________________ 
 
Age: __________________ 
 
Sport in which you participate: _______________________ 
Playing position: ___________________________ 
Category: __________________________________ 

72 
 
 
 
 
 
 
 
 
strongly disagree 
Disagreement 
Neutral 
In agreement 
totally agree 
I don't understand 
1. I often have trouble concentrating while competing. 
 
 
 
 
 
 
2. While I sleep I usually think about the match or 
competition in which I am going to participate. 
 
 
 
 
 
 
3. I have great confidence in my technique. 
 
 
 
 
 
 
4. Sometimes I don't find myself motivated to train. 
 
 
 
 
 
 
5. I get along very well with other team members. 
 
 
 
 
 
 
6. I rarely feel tense enough for tension to negatively 
interfere with my performance. 
 
 
 
 
 
 
7. I often mentally rehearse what I should do just before 
I start my participation in a competition. 
 
 
 
 
 
 
8. In most competitions I am confident that I will do 
well. 
 
 
 
 
 
 
9. When I do it wrong, I tend to lose concentration. 
 
 
 
 
 
 
10. It doesn't take much to shake my self-confidence. 
 
 
 
 
 
 
11. I care more about my own performance than the 
performance of the team. 
 
 
 
 
 
 
12. I am often “scared to death” in the moments before 
the start of a competition. 
 
 
 
 
 
 
13. When I make a mistake I have a hard time forgetting 
it to concentrate on what I have to do. 
 
 
 
 
 
 
14. Any little injury or bad training can weaken my self-
confidence. 
 
 
 
 
 
 
15. I set goals that I must achieve and I usually achieve 
them. 
 
 
 
 
 
 

73 
 
16. Sometimes I feel intense anxiety while participating 
in a test. 
 
 
 
 
 
 
17. During my performance in a competition my attention 
seems to fluctuate back and forth between what I have 
to do and other things. 
 
 
 
 
 
 
18. I like to work with my teammates. 
 
 
 
 
 
 
19. I have frequent doubts about my chances of doing 
well in a competition. 
 
 
 
 
 
 
20. I spend a lot of energy trying to be calm before a 
competition starts. 
 
 
 
 
 
 
21. When I start doing it wrong, my confidence drops 
quickly. 
 
 
 
 
 
 
22. I think team spirit is very important 
 
 
 
 
 
 
23. When I mentally practice what I have to do, I “see” 
myself doing it as if I were looking at myself on a 
television monitor. 
 
 
 
 
 
 
24. Generally, I can continue to participate (play) with 
confidence, even if it is one of my worst 
performances. 
 
 
 
 
 
 
25. When I prepare to participate in a test, I try to 
imagine, from my own perspective, what I will see, 
do or notice when the situation is real. 
 
 
 
 
 
 
26. My self-confidence is very unstable. 
 
 
 
 
 
 
27. When my team loses I feel bad regardless of my 
individual performance. 
 
 
 
 
 
 
28. When I make a mistake in a competition I get very 
anxious. 
 
 
 
 
 
 
29. Right now, the most important thing in my life is to 
do well in my sport. 
 
 
 
 
 
 
30. I am effective in controlling my stress. 
 
 
 
 
 
 
31. My sport is my whole life. 
 
 
 
 
 
 

74 
 
32. I have faith in myself. 
 
 
 
 
 
 
33. I usually find myself motivated to improve myself 
day by day. 
 
 
 
 
 
 
34. I often lose concentration during the competition as a 
result of decisions by referees or judges that I consider 
unwise and go against me or my team. 
 
 
 
 
 
 
35. When I make a mistake during a competition (or 
during a match) I often worry about what other people 
like the coach, teammates or someone in the audience 
think. 
 
 
 
 
 
 
36. The day before a competition I am usually too 
nervous or worried. 
 
 
 
 
 
 
37. I usually set myself goals whose achievement 
depends 100% on me instead of goals that do not 
depend only on me 
 
 
 
 
 
 
38. I believe that the specific contribution of all the 
members of a team is extremely important for the 
success of the team. 
 
 
 
 
 
 
39. It is not worth devoting as much time and effort as I 
dedicate to sport 
 
 
 
 
 
 
40. In competitions I usually encourage myself with 
words, thoughts or images. 
 
 
 
 
 
 
41. I often lose concentration during a competition 
because I worry or think about the final result 
 
 
 
 
 
 
42. I usually accept criticism well and try to learn from it. 
 
 
 
 
 
 
43. I easily concentrate on what is most important at each 
moment of a competition. 
 
 
 
 
 
 
44. I find it hard to accept that the work of other team 
members is highlighted more than mine. 
 
 
 
 
 
 
45. When a competition ends, I analyze my performance 
objectively and specifically (that is, considering real 
 
 
 
 
 
 

75 
 
events and each section of the competition or match 
separately. 
46. I often lose focus on the competition as a result of 
unsportsmanlike performance or comments from 
opponents. 
 
 
 
 
 
 
47. I am very concerned about the decisions that the 
coach may make regarding me during a competition. 
 
 
 
 
 
 
48. I do not mentally rehearse, as part of my training plan, 
situations that I need to correct or improve. 
 
 
 
 
 
 
49. During training I am usually very focused on what I 
have to do. 
 
 
 
 
 
 
50. I usually set priority goals before each training 
session and each competition. 
 
 
 
 
 
 
51. My confidence in the competition depends to a large 
extent on the successes or failures in the previous 
competitions 
 
 
 
 
 
 
52. My motivation largely depends on the recognition I 
get from others. 
 
 
 
 
 
 
53. The coach's instructions, comments and gestures 
often negatively interfere with my concentration 
during the competition. 
 
 
 
 
 
 
54. I usually trust myself even in the most difficult 
moments of a competition. 
 
 
 
 
 
 
55. I am willing to make any effort to be better and better. 
 
 
 
 
 
 
 
CPRD Answer Sheet 
Date: 
Colima, Col. On __________ of the month of _______________________ 
year_________ 
 
Surname name: __________________ 
 
Age: __________________ 

76 
 
 
Sport in which you participate: _______________________ 
 
Playing position: ___________________________ 
 
Category: __________________________________ 
stress management 
Influence of performance 
evaluation 
Motivation 
item or question 
strongly disagree 
Disagreement 
Neutral 
In agreement 
totally agree 
item or question 
strongly disagree 
Disagreement 
Neutral 
In agreement 
totally agree 
item or question 
strongly disagree 
Disagreement 
Neutral 
In agreement 
totally agree 
1 
4 
3 
2 
1 
0 
9 
4 
3 
2 
1 
0 
4 
4 
3 
2 
1 
0 
3 
0 
1 
2 
3 
4 
16 
4 
3 
2 
1 
0 
15 
0 
1 
2 
3 
4 
6 
0 
1 
2 
3 
3 
28 
4 
3 
2 
1 
0 
29 
0 
1 
2 
3 
4 
8 
0 
1 
2 
3 
4 
34 
4 
3 
2 
1 
0 
31 
0 
1 
2 
3 
4 
10 
4 
3 
2 
1 
0 
35 
4 
3 
2 
1 
0 
33 
0 
1 
2 
3 
4 
12 
4 
3 
2 
1 
0 
42 
0 
1 
2 
3 
4 
39 
4 
3 
2 
1 
0 
13 
4 
3 
2 
1 
0 
44 
4 
3 
2 
1 
0 
49 
0 
1 
2 
3 
4 
14 
4 
3 
2 
1 
0 
46 
4 
3 
2 
1 
0 
55 
0 
1 
2 
3 
4 
17 
4 
3 
2 
1 
0 
47 
4 
3 
2 
1 
0 
Direct score: 
 
19 
4 
3 
2 
1 
0 
51 
4 
3 
2 
1 
0 
20 
4 
3 
2 
1 
0 
52 
4 
3 
2 
1 
0 
21 
4 
3 
2 
1 
0 
53 
4 
3 
2 
1 
0 
24 
0 
1 
2 
3 
4 
Direct score: 
 
26 
4 
3 
2 
1 
0 
30 
0 
1 
2 
3 
4 
32 
0 
1 
2 
3 
4 
36 
4 
3 
2 
1 
0 
41 
4 
3 
2 
1 
0 
43 
0 
1 
2 
3 
4 
54 
0 
1 
2 
3 
4 

77 
 
Direct score: 
 
 
 
 
 
 
 
stress 
management 
Influence of evaluation on 
performance 
Motivation 
Mental 
ability 
team 
cohesion 
99 
77-80 
42-45 
30-31 
31-34 
24 
95 
69 
38 
27 
28 
- 
90 
64 
3. 4 
26 
26 
23 
85 
61 
33 
25 
25 
22 
80 
58 
31 
23 
24 
- 
 
75 
56 
29 
- 
- 
21 
70 
54 
28 
22 
23 
- 
65 
52 
27 
21 
- 
20 
60 
50 
- 
20 
22 
- 
Mental ability 
team cohesion 
item or question 
strongly disagree 
Disagreement 
Neutral 
In agreement 
totally agree 
item or question 
strongly disagree 
Disagreement 
Neutral 
In agreement 
totally agree 
2 
4 
3 
2 
1 
0 
5 
0 
1 
2 
3 
4 
7 
0 
1 
2 
3 
4 
11 
4 
3 
2 
1 
0 
23 
4 
3 
2 
1 
0 
18 
0 
1 
2 
3 
4 
25 
0 
1 
2 
3 
4 
22 
0 
1 
2 
3 
4 
37 
0 
1 
2 
3 
4 
27 
0 
1 
2 
3 
4 
40 
0 
1 
2 
3 
4 
38 
0 
1 
2 
3 
4 
45 
0 
1 
2 
3 
4 
Direct score: 
 
48 
4 
3 
2 
1 
0 
50 
0 
1 
2 
3 
4 
Direct score: 
 

78 
 
55 
48 
26 
- 
21 
19 
 
50 
46 
24 
19 
- 
- 
 
45 
44 
23 
18 
20 
18 
40 
42 
22 
17 
- 
- 
35 
40 
21 
- 
19 
17 
30 
39 
20 
16 
18 
16 
25 
36 
19 
15 
17 
- 
 
20 
3. 4 
18 
- 
16 
15 
15 
30 
16 
14 
- 
14 
10 
27 
15 
12 
15 
13 
5 
21 
12 
11 
13 
11 
1 
0-14 
0-7 
0-8 
0-11 
0-1 
 
14.1.7 Annex 7: Correct weighing according to ISAK guidelines 
The measurement of the taking of body weight is without clothes. This can be estimated by 
weighing the clothing or clothing similar to that of the subject to be measured whose value 
is subtracted from the previously recorded on the scale. Generally, body mass in minimal 
clothing is accurate enough. Your mass should be evenly distributed on both feet on the scale. 
 
 
14.1.8 Annex 8: Study authorization letter issued by the ISFPG institution. 
Colima, Colima, on _______________________ _______, ___________ 
I ______________________________________________________ director of the school 
____________________________________________________________ 
domiciled 
at 
________________________________________ authorize the student of the Master of 
Medical Sciences at the University of Colima Alexis Adan Lopez Maria with identification 
number 20106199 to apply the corresponding procedures for his research study "Effect of 
water of coconut compared with oral electrolytes on hydration status in adolescents who 
perform competitive aerobic physical exercise. RCT, double blind.” towards all the students 

79 
 
trained under my command in inter-institutional issues. In the same way, I promise to be 
accessible in the required times and the established space. This document is issued for 
subsequent purposes. 
Attentively: 
 
                                ___________________________________________ 
Name and signature of the director of the institution 
 
 
 
 
14.1.9 Annex 9: Request letter to carry out research within the ISFPG 
 
Colima, Colima, on ______________________________, ___________ 
P.SBD Enrique Gonzalez Tapia 
Academic director Mario Guillermo de Anda Chavez 
We hereby request authorization so that the student Alexis Adan Lopez Maria student of the 
third semester of the Master in Medical Sciences with identification number 20106199 can 
carry out the application of the corresponding procedures to carry out the research project 
entitled "Effect of water of coconut compared with oral electrolytes on hydration status in 
adolescents who perform competitive aerobic physical exercise. RCT, double blind.”  within 
the facilities of the educational institution (DOSA). The project is attached to the ethical 
considerations of the Declaration of Helsinki and the Law General Health and was approved 
by the Research Ethics Committee of the Institute State of Colima Cancerology whose letter 
is attached to the document. 
Without more for the moment, we appreciate the attention provided and we hope for a 
prompt response. Best regards. 
Attentively 
 
_____________________________                   _____________________________ 
                    Master's coordinator                                                   Student advisor 
 

80 
 
14.1.10Annex 10: Informed consent letter for father, mother, or guardian. 
 
INFORMED CONSENT LETTER 
Colima, Col. On _________of _____________ the year _________ 
I ______________________________________________________ declare that I have 
been fully explained by the student of the Master of Medical Sciences of the University of 
Colima: Alexis Adan Lopez Maria with identification 20106199 about the research process 
which leads to title “Effect of coconut water compared to oral electrolytes on hydration status 
in adolescents who perform physical exercise. Clinical trial, double-blind” with the objective 
of comparing 2 drinks on the state of hydration, in this way in full use of my faculties, I give 
consent for my son ______________________________________________ to participate 
in the research study, agreeing with the performance of the process where 4 sessions of 
aerobic physical training will be carried out without any compensation and with benefits for 
my son's health since the quantity, type of drink and hydration times will be taken care of at 
all times, ensuring proper hydration, as well as being aware of possible risks such as: cramps, 
headache, nausea, vomiting, dizziness, or sports injury. I accept that the researcher performs 
anthropometric measurements such as: weight, height and total body water through 
bioimpedance, in addition to the administration of hydrating drinks and urine collection. By 
signing this document, I agree to provide personal information, providing my full name, age, 
and/or any information requested to carry out the research study, taking care of the anonymity 
of the identities and clarifying that the data obtained is only for research purposes. 
Without prejudice to the procedures to be carried out, I declare that I have full capacity, 
conscience, and lucidity to decide and accept the aforementioned procedures under my full 
responsibility. 
 
________________________________                   ________________________________ 
Father's name and signature                                                Mother's name and signature  
 
 

81 
 
14.1.11Annex 11: Informed assent letter for the minor. 
 
Colima, Col. On _______of _________________ the year _________ 
Me, Alexis Adan Lopez Maria, responsible for the research project “Effect of coconut water 
compared to oral electrolytes on hydration status in adolescents who perform physical 
exercise. Clinical trial, double blind” I offer the following information in order to obtain the 
consent of the subjects that will be studied in the program. The objective of this research 
project is to compare the effect of coconut water vs oral electrolytes in adolescents under a 
test of physical exercise. To carry out the study, patients must ingest a weekly dose of the 
aforementioned beverages, they must also comply with physical exercise sessions, follow a 
meal plan, perform anthropometric measurements (weight, height and total body water by 
bioimpedance), urine collection and mental health screening, plus routine follow-up. 
Likewise, the anonymity of the identities is taken care of, clarifying that the data obtained is 
only for research purposes. 
All study subjects who agree to participate in this study assume the risk of having some side 
effects related to the intake of beverages, exercise or food plan. Among the symptoms that 
could present are: generalized fatigue, drowsiness, dizziness or vomiting. 
The duration of the study will be a period of 4 sessions, in which the subjects must drink the 
drink assigned to them within the facilities on a weekly basis. If the subject presents any 
disease or severity during the course of the study that makes it impossible for him to continue, 
the treatment will be suspended. 
I, ________________________________________________ after having read and 
understood the entire procedure to be carried out, I accept to be part of the aforementioned 
research project and being aware that I can withdraw from the study without being forced to 
continue. 
_______________________________                        _______________________________ 
[Signature of the participant]                                         [Signature of the person in charge] 
_______________________________                          _______________________________ 
[Witness signature 1]                                                                  [Witness signature 2] 

82 
 
 
14.1.12Annex 12: Letter approved by the Research Ethics Committee of the State 
Institute of Cancerology in Spanish and English. 
 
 

83 
 
 

84 
 
14.2 Viability 
14.2.1 Feasibility 
This project is feasible since, according to the financial calculation that was estimated, the 
total inputs could be covered by the student, in addition to the fact that it is planned to attend 
the call for the CONACYT scholarship plus other external sources of financing. Additionally, 
it complies with ethical aspects, classifying itself as minimal risk, without compromising the 
patient's health. 
14.2.2 Human Resources 
Those responsible for the project: D in C Carmen Alicia Sánchez Ramírez, D in C Fabian 
Rojas Larios, D in C Yunue Flores Ruelas and LN Alexis Adan Lopez Maria, student of the 
Master of Medical Sciences at the University of Colima, with the present project. 
14.2.3 Financial resources 
For the development of this research project, a good part of the resources to carry it out are 
already available, and they are mentioned in the following table. In relation to the costs of 
computer equipment, software and office supplies, they will be covered by the principal 
investigator. 
 
14.2.4 Financing 
ITEM 
NO. 
DESCRIPTION OF THE ARTICLE 
PRESENTATION 
AMOUNT 
PRICE 
STATIONERY 
1 
WHITE BOND SHEETS LETTER SIZE 
PACK OF 100 SHEETS 
1 
$55.00 
two 
HALF EYEBROW LETTER SIZE FOLDER 
PACKAGE W/100 PCS 
1 
$82.00 
3 
PEN MEDIUM POINT 1.0 MM 
PACKAGE WITH 3 
two 
$56.00 
4 
MEDIUM POINT PENCIL NO. 2 
PACKAGE W/6 PCS 
1 
$28.00 
5 
YELLOW TEXT MARKER 
PACKAGE WITH 2 PCS 
1 
$25.00 
6 
LIQUID CORRECTOR PEN 
PART 
1 
$30.00 
7 
RUBBER TO ERASE 
PACKAGE WITH 2 PCS 
1 
$11.00 
8 
PENCIL SHARPENER 
PART 
1 
$18.00 
9 
STAPLER 
PART 
1 
$47.00 
10 
STANDARD STAPLES 
PACK W/5,040 PCS 
1 
$25.00 
eleven 
SONY VAIO BRAND 15” LAPTOP 
PART 
1 
$10,000.00 

85 
 
HYDRATING DRINKS 
12 
COCONUT WATER 
LITERS 
156 
$5,300.00 
13 
ELECTROLIT 1.115 ML COCO® FLAVOR 
PART 
156 
$5,183.00 
LAB'S MATERIAL 
14 
TANITA MODEL BC-601 SCALE 
PART 
1 
$7,150.00 
fifteen 
SECA STADIMETERS MODEL 21317210092 
PART 
two 
$5,740.00 
16 
HERMETIC JARS FOR SAMPLES 
BOX W/200 
300 
$1,500.00 
17 
MEASURING GLASSES 
PART 
44 
$2,860.00 
INFRASTRUCTURE MATERIAL 
18 
REFRIGERATOR 
PART 
1 
$4000.00 
19 
HANDHELD REFRACTOMETER 
PART 
1 
$3000.00 
TOTAL PROJECT COST 
$45,110 
 
 
14.3 Schedule of activities 
ACTIVITIES 
2020 
2021 
2022 
SEP-OCT 
NOV-DEC 
JAN-FEB 
MAR-APR 
MAY-JUN 
JUL 
AUG-SEP 
OCT-NOV 
DEC 
JAN-FEB 
MAR-APR 
MAY-JUN 
JUL 
AUG-SEP 
OCT-NOV 
DEC 
Development and evaluation of 
the research project protocol. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Evaluation of the study 
population. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Selection of adolescents who will 
participate in the research. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Realization of the protocol in the 
field. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Analysis of results 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Thesis writing. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Obtaining the degree of Master in 
Medical Sciences 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

86 
 
Writing and submission of article 
for publication. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
14.3.1 CONSORT check list 
CONSORT 
Section / Topic 
Question 
(37) 
Check list 
Evaluator 1 
Evaluator 2 
Title and abstract 
1st 
Identification in title as randomized 
 
 
1 B 
Structured summary of the design, 
methodology, results and conclusions 
 
 
Introduction 
 
 
Background and 
objectives 
2nd 
scientific background 
 
 
2b 
Specific objectives or hypothesis 
 
 
methods 
 
 
Study design 
3rd 
Description of trial design, including 
allocation ratio 
 
 
3b 
Important changes in methods before the start 
of the trial with reasons for them 
 
 
Participants 
4th 
Selection criteria. 
 
 
4b 
Conditions and locations where the data was 
collected 
 
 
Interventions 
5 
Interventions for each group with sufficient 
detail to allow replication, including how and 
when they were administered 
 
 
Results 
6th 
Prespecified definition of primary and 
secondary outcomes, including how and when 
they were assessed 
 
 
6b 
Any changes to the trial after the start of the 
trial, with reasons 
 
 
Sample size 
7th 
How was the sample size determined? 
 
 
7b 
When applicable, explanation of interim 
analysis and detention guidelines. 
 
 
randomization 
 
 

87 
 
Sequence of generation, 
assignment and 
implementation 
8th 
Method used to generate the randomized 
allocation sequence 
 
 
8b 
Randomization type, restriction details (blocks 
and size) 
 
 
9 
Mechanism used for the random assignment 
sequence describing the steps taken to hide the 
sequence until the interventions were assigned 
 
 
10 
Who generated the assignment sequence, who 
recruited the participants, who assigned the 
participants to the interventions? 
 
 
blinding 
11th 
If done, who was blinded after allocation of 
interventions (participants, investigators, those 
assessing outcomes) and how. 
 
 
11b 
If relevant, description of similarity of 
interventions 
 
 
Statistical methods 
12th 
Statistical methods used to compare groups for 
primary and secondary outcomes 
 
 
12b 
Methods for additional analyses, such as 
subgroup analyzes and adjusted analyzes 
 
 
Results 
 
 
Flow of participants 
(Develop CONSORT 
diagram) 
13th 
For each group, the number of participants 
who were randomly assigned, with the 
intention to receive treatment, and who were 
analyzed for the primary outcome 
 
 
13b 
For each group, losses and exclusions after 
randomization, with reasons. 
 
 
14th 
Dates defining the recruitment and follow-up 
periods. 
 
 
14b 
Why the trial stopped or was stopped 
 
 
fifteen 
Table showing the baseline demographic and 
clinical characteristics of each group 
 
 
16 
For each group, number of participants 
(denominator) included in each analysis and 
whether analysis was by original allocation of 
groups 
 
 

88 
 
17th 
For each primary and secondary outcome, 
results for each group, the estimated sample 
effect, precision (confidence interval) 
 
 
17b 
For binary outcomes, presentation of absolute 
and relative effect is recommended. 
 
 
18 
Results of any other analysis carried out, 
including subgroups and adjustments, 
distinguishing by default from the exploratory 
one. 
 
 
19 
All deleterious or unexpected effects in each 
group 
 
 
twenty 
Study limitations, sources of potential bias, 
imprecision and, if relevant, multiplicity of 
analyses. 
 
 
twenty-
one 
Generalization of the study findings (external 
validity) 
 
 
22 
Interpretation, consistency with results, 
balance between benefits and harms, and 
consideration of different relevant evidence 
 
 
23 
Registration number and trial name. 
 
 
24 
If available, the full trial protocol can be 
accessed. 
 
 
25 
Sources of sponsorship and other support, role 
of sponsors.