Fluid Balance During Exercise in the Heat With Water, Flavored Placebo, or a Carbohydrate-electrolyte Beverage Intake (The APEX Study)

Study Overview
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Brief Summary
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The purpose of the APEX study is to determine whether carbohydrate-electrolyte beverage intake promotes fluid balance during exercise in the heat compared with water or placebo intake.

Detailed Description
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Exercise in the heat has large effects on cardiovascular strain, the ability to regulate core body temperature, and performance because of an increase in the reliance on body fluid distribution to the skin to maintain adequate sweat rates and heat dissipation. Carbohydrate-electrolyte beverage intake during exercise in the heat may improve fluid balance and subsequent physical performance. The participants will be assigned each arm in a randomized, counterbalanced, cross-over fashion separated by at least 2 weeks. Participants will be placed in a heated environment for the duration of the exercise intervention.

Official Title
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Fluid Balance During Exercise in the Heat With Water, Flavored Placebo, or a Carbohydrate-electrolyte Beverage Intake (The APEX Study)

Conditions
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Dehydration

Intervention / Treatment
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* Other: Exercise Intervention


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Males aged 18-35 years Healthy (No uncontrolled disease) Exclusion Criteria: No medications that influence fluid balance No uncontrolled disease

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Water<br>Electrolyte- and mineral-free water with exercise intervention | Other: Exercise Intervention<br>* Exercise intervention trials will consist of a steady-state bout of exercise at  70% VO2peak and a timed performance test on a cycle ergometer in a heated environment.<br>|
| Placebo Comparator: Placebo<br>Calorie- and electrolyte-free, sweetened flavored water with exercise intervention | Other: Exercise Intervention<br>* Exercise intervention trials will consist of a steady-state bout of exercise at  70% VO2peak and a timed performance test on a cycle ergometer in a heated environment.<br>|
| Experimental: Carbohydrate-electrolyte beverage<br>Commercially-available flavored beverage carbohydrate-electrolyte beverage with Exercise Intervention | Other: Exercise Intervention<br>* Exercise intervention trials will consist of a steady-state bout of exercise at  70% VO2peak and a timed performance test on a cycle ergometer in a heated environment.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fluid Balance | Fluid balance will be determined by change in body weight during the 120 minutes steady-state exercise bout in the heat. | 120 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of fluid uptake in the GI tract | Fluid uptake in the GI tract be assessed by D20 accumulation in the plasma. | 30 minutes | 
| Amount of carbohydrate oxidized | Carbohydrate oxidation rates will be assessed by indirect calorimetry. | 120 minutes | 
| Cardiovascular responses | Heart rate and blood pressure will be assessed during exercise. | 120 minutes | 
| Thermoregulatory responses | Body temperatures will be assessed during exercise. | 120 minutes | 
| Physical Performance | Performance during the timed exercise trial will be improved with carbohydrate-electrolyte beverage intake compared with water and placebo intake. | 30 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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dehydration, fluid balance, exercise, heat, body weight, performance