Heat disorders in industry. A reevaluation of diagnostic criteria.

Morbidity rates associated with occupationally induced heat syndromes have been infrequently reported. In part this results from the inconsistency of diagnostic criteria for heat syncopy, exhaustion, and cramps. This problem is augmented by inconstant administration and completion of population survey instruments. With due regard for these shortcomings, we can provide only estimates of heat-induced morbidity, ranging between 0.12 and 1.4 cases per 1,000 man-years. To facilitate diagnosis of occupational heat stress disorders, a series of algorithms is presented for diagnosis of heat-induced syncopy, exhaustion, and cramps. A differentiation between heat-induced and heat-aggravated clinical states is proposed, and a heat disorder questionnaire with instructions for use is presented.