Effect of Energy Drink on Sport Performance and Psycho-Physiological Responses.
Condition: Physical Activity
Study type: Interventional

Summary: 
      This work aimed to examine the effects of drinking an "energy drink" upon (i) short-term
      maximal performance, (ii) reaction times and (iii) psychological factors (i.e., mood state,
      ratings of perceived exertion (RPE) and affective load) and on physiological parameters such
      as blood pressure, blood glucose, hematological parameters and other biochemical parameters.
    

Detailed description: 
      A total of 22 healthy and regularly active physical-education male students from various
      sports disciplines volunteered to participate in this study. Potential participants were
      initially screened through telephone interviews based on the inclusion criteria: 18-40 years
      of age, BMI less than 25 kg/m2, and low (<1.5g/month ) and not regular caffeine users.
      Exclusion criteria included diagnosis of any chronic metabolic disease such as type 2
      diabetes or cardiovascular disease, an auto-immune disease such as rheumatoid arthritis,
      lupus or type 1 diabetes, liver disease and the intake of any medications/ or dietary
      supplements known to influence blood glucose concentrations and/or blood pressures.

      The study was conducted according to the declaration of Helsinki and the protocol was fully
      approved (identification code: 8/16) by the review board "Local committee of the Laboratory
      of Biochemistry, CHU Habib Bourguiba, Sfax, Tunisia." After a throughout explanation of the
      protocol and responses to all questions, participants signed a written informed consent.

      Subjects were instructed to avoid nicotine, alcohol, dietary supplements, medications and all
      other stimulants and to maintain their normal dietary, sleep and physical activity patterns
      before test sessions. Caffeine and other caffeinated products (e.g., chocolate, caffeinated
      gums, caffeine containing beverages) were avoided for 48 hours and food for at least 4 hours
      before testing.

      A double blind, placebo-controlled, counterbalanced, crossover design was adopted for this
      study. The randomized order of testing was determined using free online software
      (www.randomization.com). Neither staff nor participants were informed about the names of the
      two drinks, and blinding was strictly maintained by emphasizing to both staff and
      participants that both drinks adhered to healthy principles, and that each was advocated by
      certain sports medicine experts. Two familiarization sessions were completed before
      definitive test sessions in order to eliminate any learning effects on physical performance
      and reaction time measurements. During the second familiarization session, body mass and
      height were recorded. Each participant visited the laboratory for two formal test sessions,
      drinking a caffeine-containing ED (RB) and a caffeine and taurine free beverage drink (PL).
      All sessions were arranged in the early evening hours to avoid any time of day effects. The
      two definitive test sessions were separated by an interval of seven days to allow sufficient
      recovery between tests and to ensure caffeine washout. To avoid identification, two opaque
      and unmarked cans of RB or PL were ingested by each participant (i.e., 500 mL) in the
      presence of a researcher. The two drinks were similar in volume, texture, and appearance. One
      can of RB drink (i.e., 250ml) contained 80 mg of caffeine, 1 g of taurine, 27 g of
      carbohydrates, 0.6 g of protein, 5 mg vitamin B6 and 487 kJ of energy. The PL drink was
      prepared by an agri-food engineer; it did not contain any caffeine or taurine, but comprised
      carbonated water, carbohydrates, citric acid lemon juice reconstituted from concentrate (1
      %), supplemented by flavorings, of sodium citrate, acesulfame K, sucralose, potassium sorbate
      and RB (a flavoring that contains propylene glycol E1520 (0.23 mL).

      Beverages were prepared, shaken and chilled in a refrigerator at 14h00 by an investigator who
      took no part in the test sessions or data analysis, but prepared the alphanumeric code
      identifying the tested drink. At 17h00, the cooled beverages were served in sealed plastic
      opaque water bottles and consumed using an opaque straw. Participants were instructed to
      drink the fluid quickly (within 1±0.5 min) 60 minutes before their test session and not to
      discuss or compare tastes or to make any assumptions about what they had ingested. The
      interval of 60 minutes was chosen as optimal for a complete caffeine absorption and thus a
      peaking of a caffeine concentration .

      Subjects were supervised by staff to ensure that they drank the entire quantity of fluid, and
      no exchange of bottles was allowed. The last standardized meal (i.e., lunch) before the
      beginning of the test session was taken at 13h00. Temperature and relative humidity of the
      laboratory were similar over the test sessions, with a temperature of around 22°C and a
      relative humidity between 45 and 55 %. During each test session (from 18h00), resting blood
      glucose and blood pressures were measured and the participants completed the POMS
      questionnaire.

      A 5-min treadmill warm-up was performed. After that, the reaction time, and handgrip force
      were determined, and the 30-s Wingate test was performed. RPE scores, blood glucose and blood
      pressures were then measured, and the affective load was calculated. To investigate the
      effects of RB on the acute physiological and psychological responses to exercise, blood
      measures and psychological test measures were collected immediately pre- and post-exercise.
    

Intervention name(s): Energy Drink; Placebo Drink
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Each participant visited the laboratory for two formal test sessions, drinking a caffeine-containing ED (RB) and a caffeine and taurine free beverage drink (PL). All sessions were arranged in the early evening hours to avoid any time of day effects. The two definitive test sessions were separated by an interval of seven days to allow sufficient recovery between tests and to ensure caffeine washout. To avoid identification, two opaque and unmarked cans of RB or PL were ingested by each participant (i.e., 500 mL) in the presence of a researcher. The two drinks were similar in volume, texture, and appearance. One can of RB drink (i.e., 250ml) contained 80 mg of caffeine, 1 g of taurine, 27 g of carbohydrates, 0.6 g of protein, 5 mg vitamin B6 and 487 kJ of energy.; The PL drink was prepared by an agri-food engineer; it did not contain any caffeine or taurine, but comprised carbonated water, carbohydrates, citric acid lemon juice reconstituted from concentrate (1 %), supplemented by flavorings, of sodium citrate, acesulfame K, sucralose, potassium sorbate and RB (a flavoring that contains propylene glycol E1520 (0.23 mL).
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: A double blind, placebo-controlled, and counterbalanced crossover design was used for this work
Masking: Single (Participant)
Primary purpose: Supportive Care
Keywords: Energy drinks; Exercise; Physiological response; Mood State; Fatigue