Effects of Three Hydration Beverages on Exercise Performance during 60 Hours ofSimulated Desert Exposure

摘要

Without adequate hydration, profound heat stress and dehydration can occur inmilitary forces operating in hot environments. The purpose of this study was to evaluate the effectiveness of three beverages on temperature regulation, Cardiovascular response, and work performance during prolonged heat exposure. Subjects lived in a climatic chamber for 3 days (60 h) in simulated desert conditions varying from 25 to 45 deg C, 20% relative humidity. Three submaximal 11 exercise bouts were performed at 4-h intervals each day. Full military combat clothing was worn during the exercise tests. Subjects randomly consumed three beverages, a water placebo, a 5 % carbohydrate-electrolyte drink, and a 4 % carbohydrate-electrolyte drink containing 1 % glycerol throughout each test. Physiological parameters remained within expected limits during the experiment. During exercise, rating of perceived exertion and heart rate were similar for all beverages, but oxygen consumption, body (rectal) and average skin temperatures, and sweat rate differed among beverages. We conclude that carbohydrate-electrolyte beverages, preferably with a small amount of glycerol.