Accession Number : ADA118669

Title :   Hypohydration and Exercise: Effects of Gender, Environment and Heat Acclimation,


Personal Author(s) : Sawka,Michael N ; Toner,Michael M ; Francesconi,Ralph P ; Pandolf,Kent B

PDF Url : ADA118669

Report Date : 19 Jul 1982

Pagination or Media Count : 33

Abstract : The purpose of this study was to examine the effects of heat acclimation and subject gender on treadmill exercise in a comfortable(20 C, 40% rh), a hot-dry (49 C, 20% rh) and a hot-wet (35 C, 79% rh) environment while subjects were hypo- or euhydrated. Six male and six female subjects, matched for maximal aerobic power and percent body fat, attempted two exercise tests in environment both before and after a 10-day heat acclimation program. One exercise tests was attempted when euhydrated and the other test when hypohydrated (-5.0% from baseline body weight). In general, no significant (P 0.05) differences were noted between men and women at the completion of exercise for rectal temperature (Tre), mean skin temperature (Tsk) or heart rate (HR) during any of the experimental conditions. Hypohydration was generally found to increase Tre and HR responses as well as to decrease sweat rate values while not altering Tsk responses. In the hypohydration experiments, heat acclimation significanlty reduced Tre (0.19 C) and HR (13 b min) responses in the comfortable environments, but reduced only HR responses in the hot-dry 21 b min) and hot-wet (21 b min) environments. The percent findings indicate that men and women respond in a physiologically similar manner to hypohydration during exercise. It is also suggested that an expanded plasma volume, mediated by heat acclimation, may have attenuated Tre and HR responses during hypohydration.

Descriptors :   *Acclimatization, *Dehydration, *Exercise(Physiology), *Heat stress(Physiology), Treadmills, Aerobic processes, Males, Females, Adipose tissue, Heart rate, Perspiration, Rates, Body temperature

Subject Categories : Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE