Rapid onset of severe heat illness: a case report.

Aviators flying extended periods in hot environments are known to be at risk for heat-related illness. The risk when wearing chemical individual protective equipment (IPE) is increased even at relatively warm temperatures and light workloads. In this paper, we report the physiological responses of an aviator who had been flying a UH-1H helicopter up to 6 h/d clothed in full IPE on 6 consecutive days prior to the sudden onset of heat illness. His performance during the study was normal, and no clear physiological derangements were noted prior to his symptoms. The rapid evolution of his symptoms after voicing no complaints provides a graphic illustration of the difficult predictability and initial central nervous system effects of this condition.