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Thermal Stress in Seven Types of Chemical Defense Ensembles During Moderate Exercise in Hot Environments

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Final rept. May 1991-Jul 1992

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United States Air Force -USAF personnel must perform their duties in many operational environments, including those with the potential for contamination with toxic chemical warfare CW agents. This study evaluated the physiological response to thermal stress in subjects performing moderate work in current and prototype chemical protective garments including the Battle Dress Overgarment BDOBDU, BDO without BDU, United Kingdom UK undercoverallBDU, Gore-Tex rainsuitPJ-7 undercoverall, Marine Light Fighter Suit MLFS, CWU77P, PJ-7 alone, and the BDU alone. Experimental conditions were dry bulb temperature of 40 deg C 104 deg F, a wet bulb temperature of 270C 80.6 deg F, and a black globe temperature of 450C 113 deg F. Eleven subjects walked on a treadmill at 3 mph with a 5 grade incline until rectal temperature Tre rose 1.5 deg C 2.7 deg F above the starting value. Heart rate, rectal and mean skin temperature, and body heat storage were monitored continuously. Sweat evaporation and production were determined from the differences between pre- and postexperiment clothed and nude weights. Significantly longer work times, lower heart rates, lower Tmsk, and lower heat storage, were seen in the group comprised of the BDU, MLFS, CWU-77P, and PJ-7 compared to the Gore-Tex with PJ- 7, UK plus BD BDOBDU, and BDO no BDU ensembles. Suits which resulted in shorter tolerance times also caused rates of sweat production and lower sweat evaporation than the less physiologically burdensome suits. Chemical protective ensembles, Thermal stress, Clothing, Exercise.

Subject Categories:

  • Stress Physiology
  • Military Operations, Strategy and Tactics
  • Protective Equipment

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