Heat Strain and Work Tolerance Times with Varying Levels of Canadian Forces NBCProtective Clothing, Ambient Temperature, Physical Work Intensity and Work/Rest Schedules

摘要

Canadian Forces personnel must be able to sustain operations in an environmentcontaminated with nuclear, biological and/or chemical (NBC) agents. Clothing has been designed that protects the individual from a hostile NBC environment. This clothing, however, impairs body heat loss. The degree of impairment is magnified if metabolic heat production is increased and/or environmental temperature increases. The purpose of the present study, therefore, is to examine the effects of environmental temperature and metabolic rate on soldiers' physical work tolerance times (WTT) while wearing various levels of NBC clothing. Twenty-three male soldiers were allocated to exercise at either a light or heavy metabolic rate in an environmental chamber that controlled ambient conditions at either a cool (18 C) or hot (30 C) temperature. Subjects were tested wearing three levels of protective clothing: their regular combat fatigues (Low); fatigues and the NBC overgarment (Med); fatigues, NBC overgarment, rubber gloves and boots, and protective respirator (High). WTT was defined as the time until body temperature increased to 39.3 C (normal being 37 C), heart rate reached 95% of an individual's maximum, dizziness or nausea precluded further exercise, or 5 hours had elapsed.