Reflective Inserts to Reduce Heat Strain in Body Armor: Tests With and Without Irradiance

摘要

Delivered by U.S . Army Soldier IP : 153.103.190.11 Tue, 04 Dec 2007 irradiance. Aviat Space Environ Med 2007; 78:809 13. Background: This study evaluated adding reflective thermal inserts (RTI) to reduce the physiological strain during exercise-heat stress with a radiant load. RTI were used with a U.S. Army desert battle dress uniform, body armor, and helmet. Methods: Four male volunteers attempted four trials (10 min rest followed by 100 min walking at 1.56 m s 1). All trials were at 40.0 C dry bulb (Tdb), 12.4 C dew point (Tdp), 20% RH, and 1.0 m s 1 wind speed. On 2 d, there was supplementary irradiance ( I) with globe temperature (Tbg) 56.5 C and on 2 d there was no supplementary irradiance ( I) with Tbg Tdb. Trial conditions were: 1) RTI and armor with supplementary irradiance (RA I); 2) plain armor with supplementary irradiance (PA I); 3) RTI and armor with no supplementary irradiance (RA I); and 4) plain armor with no supplementary irradiance (PA I). Results: Endurance times were not significantly different among trials. With one exception, armor and helmet interior and exterior surface temperatures were not significantly different between either RA I and PA I or RA I and PA I. Temperature on the inside of the helmet in RA I (47.1 1.4 C) was significantly lower than in PA I (49.5 2.6 C). There were no differences for any physiological measure (core temperature, heart rate, mean weighted skin temperature, forehead skin temperature, sweating rate, evaporative cooling, rate of heat storage) between either RA I and PA I or RA I and PA I. Conclusions: Results showed no evidence that wearing RTI with body armor and helmet reduces physiological strain during exercise-heat stress with either high or low irradiance.