The body cools itself most efficiently by sweating and then the sweat evaporating. Should sweating be unable to meet the cooling demands of the body, heat-related illness can occur. This is a spectrum of conditions with minor symptoms such as prickly heat or heat rash, progressing to heat cramps, then heat exhaustion, and finally to heat stroke, a life-threatening medical condition.
The line between each diagnosis is not sharply drawn. Heat cramps tend to involve involuntary spasm of the large muscles of the body while heat exhaustion has more systemic complaints. These can include profuse sweating, weakness, nausea, vomiting, headaches, and muscle spasms. The affected individual may be a low grade fever. Heat stroke is a life-threatening situation where the body’s cooling system fails. The body temperature spirals out of control usually greater than 106F (41C), sweating stops and there are mental status changes like confusion, seizures, and coma.
Heat exhaustion occurs when a person exercises or works in a hot environment and sweating cannot dissipate the heat generated within the body. Often dehydration occurs because the person hasn’t replaced the water lost by sweating.