High Temperature Environments

In high temperature environments, workers can become subject to heat stress. The first effect is deterioration in performance quality with an increase in errors, due to a lack of movement precision. Reaction and movement times also increase under thermal stress. When working under heat stress, whether with a light task or heavy task, the worker's reactions will be similar to someone suffering from influenza and performance will be similarly impaired. (Tichauer, E.R. The Effects of Climate on Working Efficiency, Impetus, reprint.)

When the environmental temperature exceeds 90°F, internal body temperature rises, placing workers at risk. High relative humidity increases this risk by preventing sweat evaporation, the body's heat disposal mechanism. Heat stress can cause: heat rash, fainting, heat cramps, heat exhaustion, and heat stroke. Heat stroke is very serious and can cause death in even young, fit, athletic individuals.

	When the body is unable to cool itself through sweating, serious heat illnesses may occur. The most severe heat-induced illnesses are heat exhaustion and heat stroke. If left untreated, heat exhaustion can progress to heat stroke and possible death.
HIGH TEMPERATURE + HIGH HUMIDITY + PHYSICAL WORK = HEAT ILLNESS
OSHA 2002