Accession Number : ADA192654

Title :   Variability in Intake and Dehydration in Young Men during a Simulated Desert Walk.

Descriptive Note : Final rept. Jan 87-Feb 88,

Corporate Author : ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA

Personal Author(s) : Szlyk, Patricia C ; Sils, Ingrid V ; Francesconi, Ralph P ; Hubbard, Roger W ; Matthew, William T

PDF Url : ADA192654

Report Date : 26 Feb 1988

Pagination or Media Count : 24

Abstract : Voluntary dehydration was examined in young unacclimatized men walking under simulated desert conditions. Thirty-three subjects (20-33 yrs) walked on a treadmill for 30 min.h(-1) for 6 h in a hot environment (40 C db/ 26 C wb, 4.02 km.h(-1) windspeed). Cool (15 C) water was provided ad libitum in canteens. Two subpopulations of individuals were identified: those drinkers (D) (n=20) who maintained body weight loss at less than 2% and those who were reluctant to drink (reluctant drinkers, RD) (n=13) and lost more than 2% body weight (BW) despite continual availability of cool water. RD consumed 31% less water than D and this resulted in a significantly greater BW loss in RD than D. However, the only statistically significant differences in plasma indices of hypohydration were the higher final plasma Na+ and protein levels in RD. Rectal temperature was higher in the RD, whereas final heart rates were unaffected. Our results indicate that about 40% of young adult males may be reluctant to drink, thus will voluntarily dehydrate even when cool water ad libitum during intermittent exercise in the heat. The reduced intake of reluctant drinkers may be critical in predisposing them to increased risk of dehydration and heat injury.

Descriptors :   *DEHYDRATION, *EXERCISE(PHYSIOLOGY), *WALKING, *DRINKING WATER, ADULTS, AVAILABILITY, BODY TEMPERATURE, BODY WEIGHT, CONTAINERS, COOLING, DESERTS, ENVIRONMENTS, HEART RATE, HEAT, HIGH TEMPERATURE, MALES, PLASMAS(PHYSICS), PROTEINS, RECTUM, RISK, SIMULATION, WATER, WEIGHT REDUCTION, WOUNDS AND INJURIES

Subject Categories : Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE