Accession Number : ADA328063

Title :   Thermoregulatory Consequences of Upper Body Versus Lower Body Exercise.

Descriptive Note : Final rept.,

Corporate Author : NAVAL HEALTH RESEARCH CENTER SAN DIEGO CA

Personal Author(s) : Canine, M. K. ; Bothorel, B. ; Habib, C. M. ; Trone, D. W. ; Vurbeff, G. K.

PDF Url : ADA328063

Report Date : 12 MAY 1997

Pagination or Media Count : 27

Abstract : The purpose of this study was to examine the effects of exercise mode on heat strain when cooling was provided by liquid-based microclimate cooling. Eight males exercised 20 min every half hour for a total of 120 min in a hot environment (49 deg C, 20% relative humidity) while dressed in a chemical protective overgarment. Subjects completed the following four tests: upper body exercise (UBE) with no cooling (NC), UBE with cooling (C), lower body exercise (LBE) with NC, and LBE with C. Work rates were selected to elicit an oxygen uptake of 1.2 L/min. Heart rate (HR), rectal temperature (T sub re), and whole body sweat rate (SR) were measured as heat strain indicators. Heat strain indices were similar between UBE and UBE when no cooling was provided. When cooling was provided, SR and T sub re were similar between exercise modes, but HR was significantly higher during UBE-C (109 +/- 19 beats.min-1) than during UBE-C (96 +/- 10 beats.min-1). Heat transfer to the cooling system was greater during IBIS than during UBE, possibly due to the lower efficiency in performance of LBE. Thus, whole body heat transfer under these conditions may be related to metabolic heat production rather than to region of muscular activity.

Descriptors :   *THERMODYNAMICS, *LIQUID COOLING, *HEAT STRESS(PHYSIOLOGY), *BODY TEMPERATURE, *EXERCISE(PHYSIOLOGY), HEAT TRANSFER, EFFICIENCY, METABOLISM, SAFETY, STANDARDIZATION, TEMPERATURE CONTROL, MUSCLES, PROTECTIVE CLOTHING, HEART RATE, HOT REGIONS, OXYGEN CONSUMPTION, PERSPIRATION, HEAT PRODUCTION(BIOLOGY).

Subject Categories : Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE