Heat disorders are a group of related illnesses caused by prolonged exposure to hot temperatures, restricted fluid intake, or failure of the body's temperature regulation mechanisms. Disorders related to heat exposure include heat cramps, heat exhaustion, and heat stroke (also called sunstroke). Heat stroke is especially dangerous and requires immediate medical attention.

As perspiration evaporates from the skin during hot weather, the body is cooled. Salt helps the cells retain water. If the body loses too much salt and fluids, the symptoms of dehydration can occur. In hot weather, a healthy body loses enough water to cool itself while creating the lowest level of chemical imbalance. The healthy body maintains a temperature of approximately 98.6°F (37°C) regardless of surrounding conditions.

Heat cramps are the least severe of the heat-related illnesses. They are often the first signal that the body is having difficulty with increased...