Heat injuries are more common than people think. Heat cramps are the most common. They usually affect the calf or hamstring muscles and respond to gentle stretching and to re-hydration - especially with an electrolyte solution.

Heat syncope is fainting due to heat/dehydration. This condition responds to cooling (like a sponge bath), lying down, and drinking fluids.

Heat edema is swelling of the hands or feet from heat. People sometimes get this condition when initially exposed to hot weather and it usually goes away as the person adjusts to the heat.

Heat tetany is tingling (especially of the wrists). Hyperventilation in hot weather can cause heat tetany.

Heat exhaustion usually entails a temperature of 101 to 104, headache, nausea, vomiting, dizziness, and fainting. It is important to recognize and treat heat exhaustion immediately. Treatment includes cooling, fans, drinking liquids, and applying ice over the groin and armpits). People typically respond well but prompt treatment is necessary in order to prevent the condition from progressing to heat stroke where treatment may no longer be effective.

Heat stroke is very serious. A person's temperature rises over 104 degrees and he or she has an altered mental status. 50% of those with heat stroke die from it. There are two types of heat stroke -- exertional, with profuse sweating, and classic, in which the skin is hot and dry.Classic heat stroke builds up over days and is most common in infants and in the elderly. It is a true emergency.