Rehydration Following Exercise-Induced Dehydration

Rehydration Following Exercise-Induced Dehydration: Beverage Formula Effects in Team Sport Athletes

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.

Study Overview

• Status: Completed
• Conditions: Dehydration Related to Exercise
• Intervention / Treatment: Other: Water with flavoring and non-nutritive sweetener.; Other: High-Na low-CHO beverage; Other: Low-Na high-CHO beverage

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.

• Study Type: Interventional
• Enrollment (Actual): 26
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60608
      • University of Illinois

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Male

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo; Water with flavoring and non-nutritive sweetener.	Other: Water with flavoring and non-nutritive sweetener.; A volume of fluid (water) was given after exercise to return each subject's body mass (to euhydration).
Experimental: High-Na low-CHO beverage; Beverage containing sodium concentration of 40 to 50 mEq/L and carbohydrate concentration between 310 and 350 mmol/L.	Other: High-Na low-CHO beverage; A volume of fluid (high-Na, low-CHO) was given after exercise to return each subject's body mass (to euhydration).
Experimental: Low-Na high-CHO beverage; Beverage containing sodium concentration of 15 to 25 mEq/L and carbohydrate concentration between 120 and 160 mmol/L.	Other: Low-Na high-CHO beverage; A volume of fluid (low-Na, high-CHO) was given after exercise to return each subject's body mass (to euhydration).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rehydration	Fluid retained to rehydrate the body as a percentage of volume of beverage ingested.	8 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body weight	Change in body mass from the start of data collection.	8 hours

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total body water	Change in estimated total body water from the start of data collection.	8 hours

Collaborators and Investigators

• Sponsor: University of Illinois at Chicago
• Collaborators: Abbott Nutrition
• Investigators: Principal Investigator: Craig Horswill, PhD, UIC

Study record dates

Study Major Dates

• Study Start: July 1, 2013
• Primary Completion (Actual): May 1, 2015
• Study Completion (Actual): May 1, 2016

Study Registration Dates

• First Submitted: October 28, 2013
• First Submitted That Met QC Criteria: November 1, 2013
• First Posted (Estimate): November 3, 2013

Study Record Updates

• Last Update Posted (Estimate): June 2, 2016
• Last Update Submitted That Met QC Criteria: May 31, 2016
• Last Verified: May 1, 2016

More Information

Terms related to this study

• Keywords: exercise; water; carbohydrate; dehydration; sodium; rehydration
• Additional Relevant MeSH Terms: Pathologic Processes; Metabolic Diseases; Water-Electrolyte Imbalance; Dehydration
• Other Study ID Numbers: AN-US-1307