The body normally cools itself by sweating. But under some conditions, sweating just won't do the trick. In such cases, a person's body temperature rises rapidly. Damage to the brain or other vital organs could result should a person's body temperature remain elevated for an extended period. The first signs of problems are heat cramps, which come as a result of the body's inability to replace salt lost in sweating.
Cramps can eventually lead to heat exhaustion, dehydration exhaustion or, at worst, a heat stroke.
Heat stroke is the most dangerous form of heat-related stress because there is a total collapse of the body's temperature regulating mechanisms. This condition can permanently disable or kill the victim if not treated quickly. In a normal year, nearly 200 Americans die as the result of overexposure to heat. Next to winter, no other natural hazard takes a greater toll on lives. In the 40-year period from 1936 through 1975, nearly 20,000 people were killed in the United States by the effects of heat and solar radiation.