Older and obese people are generally at high risk. Heat rashes are characterized by tiny, blister-like red vesicles on the skin accompanied by prickling sensations during heat exposure. Heat cramps Heat cramps are painful spasms of muscles used during work which occur either during or after work. The cause is heavy perspiration during hot work and subsequent consumption of large volumes of water without replacing salt loss. Heat exhaustion Heat exhaustion results from sustained exertion in hot environments, lack of acclimatization and failure to replace water lost in perspiration.
Heat exhaustion is characterized by fatigue, nausea, headache, and clammy and moist skin.
Heat syncope Heat syncope is heat-induced giddiness and fainting that occurs while a person is immobile and standing erect. It results from pooling of blood in the legs and occurs mostly among unacclimatized people. Heat stroke Heat stroke is the most serious heat stress disorder. It results from sustained exertion in hot environments by unacclimatized workers. Its cause is partial or complete failure of perspiration following sweat gland fatigue which leads to a loss of evaporative cooling and a rapid rise in core body temperature.