Accession Number:

ADA170261

Title:

Physiological Responses to WBGT-Equivalent Environments and Two Clothing Types during Simulated Desert Marches

Descriptive Note:

Corporate Author:

ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA

Report Date:

1985-12-01

Pagination or Media Count:

43.0

Abstract:

The purpose of this investigation was two-fold 1 to determine if hot-wet and hot-dry environments were equally stressful to the exercising individual and 2 to examine the effects of clothing shorts vs modified Battle Dress Uniform worn while exercising in both environments. The physiological effects of exercise in a hot-humid environment 89 F, 80 RH have been compared to those of exercise in a hot-dry environment 104 F, 28 RH, both equivalent to a WBGT temperature of 86.5 F. Six male soldiers walked on a treadmill in a climatic chamber, simulating a 3 hr desert march. Each soldier underwent five trials, on non-consecutive days warm-dry in shorts, hot-wet in shorts, hot-wet in BDU, hot-dry in shorts, and hot-dry in BDU. Many significant differences p. 05 in physiological responses were measured. We concluded that 1 the modified BDU compounded the effects of the hot-wet environment 2 different responses were observed in hot-wet vs hot-dry environments 3 increasing the humidity from 48 to 80 at 89 F resulted in an elevated rectal temperature and a reduced plasma volume post-exercise 4 significant hidromeiosis occurred only during the hot-wet BDU trial 5 sweat rate but not sweat electrolyte losses, ventilation, and change in rectal temperature varied between trials, possibly explaining why symptoms of heat exhaustion and heat stroke vary between patients and 6 equivalent physiological responses will not occur simply because hot-wet and hot-dry environments have equivalent WBGT values.

Subject Categories:

  • Stress Physiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE