Clinical trial NCT01974986: Rehydration Following Exercise-Induced Dehydration
Official title: Rehydration Following Exercise-Induced Dehydration: Beverage Formula Effects in Team Sport Athletes
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Dehydration Related to Exercise
Keywords: dehydration
exercise
rehydration
sodium
water
carbohydrate
Lead sponsor: University of Illinois at Chicago
Sponsor class: OTHER
Collaborators: name: Abbott Nutrition
First posted: 2013-11-03
Enrollment: 26
Sex: MALE
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief summary: Athletes participating in multiple training sessions a day can be at increased risk of suboptimal hydration and heat illness during their second training session, especially when the environment is hot and humid. With the exception of the absolute volume of water delivered by a rehydration beverage, characteristics of the beverage consumed play a role in the recovery and completeness of rehydration. The amount of sodium in the beverage has been shown to be a primary factor in rehydration. Recently, an effect of the carbohydrate concentration of the beverage was been reported, with its effects mediated by the renal system in response to elevated serum insulin. The purpose of this study is to compare sodium and carbohydrate effects on rehydration and recovery.

Detailed description: The effectiveness of beverage composition will be evaluated by modifying the sodium content and carbohydrate content of the beverage. Hypothesis: Completeness of rehydration will be greater in the beverage with higher sodium concentration. It is also hypothesized that electrolyte-carbohydrate beverages will promote rehydration that exceeds that of consuming placebo (water). Using a randomized balanced-treatment crossover design, physically trained males (18-35 yrs) will participate in intermittent exercise for 85 to 100 minutes in three experimental trials of variable intensity training in the heat (30 +/-3 C) followed by a rehydration-recovery period. Exercise will be done at varying intensities (intermittent intervals) ranging from 50% to nearly 100% of maximum oxygen uptake (max VO2) determined prior to the experimental trials. During the 85 to 100 min of exercise, no fluids will be given during the trial to elicit an acute reduction in body mass of approximately 2.5 to 3% (standardized for each subject). Following exercise, 100% of the volume of fluid lost will be replaced with one of the beverages. Beverages will be ingested in six aliquots over a 1-hr period given at the end of the trial. Retention of fluid will be calculated by measuring volume of urine lost at 30, 60, 135, and 210 min following ingestion of the rehydration beverage. The primary outcome variable is the percentage of fluid retained, i.e., the difference between volume ingested and cumulative urine produced in 3.5 h as a percentage of volume ingested. Body mass, urine specific gravity, total body water, and ratings of vigor and affect will be assessed prior to exercise, after exercise in a state of dehydration, and at 210 min post-exercise following rehydration. A one-way ANOVA will be used to test the hypothesis for rehydration, the primary outcome variable.

Eligibility criteria: Inclusion Criteria:

* Male, age 18-35 y, physically fit, and regularly undergoing exercise training particularly but not exclusively in team sports.

Exclusion Criteria:

* "Yes" on PAR-Q survey, symptoms or signs of exercise intolerance, VO2 max \<50 mL/kg/min, smoker

Primary outcomes:
measure: Rehydration
timeFrame: 8 hours
Secondary outcomes:
measure: Body weight
timeFrame: 8 hours
Other outcomes:
measure: Total body water
timeFrame: 8 hours
Locations:
city: Chicago
country: United States
facility: University of Illinois
state: Illinois
Study officials:
affiliation: UIC
name: Craig Horswill, PhD
role: PRINCIPAL_INVESTIGATOR
References: