Every summer, says Dr. Alicia Hastings, chairman of the Department of Physical Medicine and Rehabilitation at Howard University Hospital, there are three main kinds of heat-related problems:

*Heat cramps: Painful spasms in the exercised muscle, usually the arms or legs, occasionally the abdomen.

Treatment: Rest and water.

*Heat exhaustion, prostration, collapse: A systemwide lack of distribution of blood in response to the body's attempts to rid itself of heat. The result is weakness, dizziness, nausea and vomiting, clammy skin and ashen appearance.

"When people come in real white in the face," says John Davenport, who has officiated hundreds of Washington races since 1972, "I always tell somebody to watch that person. They almost always collapse. It seems like the blood has gone some other place."

Treatment: Immediate rest, water, elevate feet and legs. If profound collapse has occurred, contact a doctor.

*Heat pyrexia, heatstroke, sunstroke: A life-threatening medical emergency, distinguished by the absence of sweating. More frequent in the elderly, or the very young, or those with preexisting conditions, such as diabetes or alcoholism. Some medications may predispose someone to this problem, including diuretics, thyroid hormones, amphetamines and antihistamines.

Treatment: Immediate medical attention. Until the ambulance comes, you might sponge the victim with cool water or apply cold packs.