Psychological Aspects of Military Performance in Hot Environments
Book chapter 4
ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA
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The military needs to understand how mental performance, psychomotor performance, and subjective responses vary with severity of heat stress. Understanding this relationship is important because heat stress can significantly impair military performance and because psychological changes often precede the onset of critical physiological changes. Establishing well-defined relationships between climatic conditions and psychological performance has been difficult. Thermal stress researchers have attempted to identify psychological breaking points in performance, but the environmental conditions employed to simulate the natural world combinations of temperature, humidity, wind speed, and exposure time do not lend themselves to systematic, real-world organization. Therefore, it is difficult to make broad generalizations about the effects of heat stress on psychological performance. Nevertheless, there is general agreement that 1 the upper limit of heat exposure for unimpaired psychomotor performance is 90 degrees F WBGT 2 the upper limit of heat exposure for unimpaired mental performance is 85 degrees F WBGT if the service member is required to perform the task for 2 hours or longer at less than 1 hour on the task, individuals can perform proficiently at higher ambient temperatures approaching 1090 WBGT and 3 continuous repetitive tasks with relatively low arousal value tend to be the most affected. Psychological performance during ambient heat exposure is compounded for military personnel because they are often encumbered by mission-essential clothing and equipment, including, for example, chemical protective clothing or medications such as nerve-agent antidotes, or both. Realistic military training in hot environments followed by persistent practice of military tasks in hot environments will attenuate otherwise severe impairments in performance.
- Stress Physiology