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

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.

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.