Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: TUESDAY, July 25, 1995                   TAG: 9507250040
SECTION: EXTRA                    PAGE: 1   EDITION: METRO 
SOURCE: By SANDRA G. BOODMAN/THE WASHINGTON POST
DATELINE:                                 LENGTH: Medium

BY THE TIME YOU REALIZE YOU'RE HURTING FROM THE HEAT IT MAY BE TOO LATE

``The brain doesn't like being hot, the heart doesn't like being hot,'' said David Milzman, an emergency room physician at Georgetown University Hospital in Washington, D.C. In conditions of extreme heat coupled with high humidity, organ functions are seriously disrupted and crucial cells and proteins in the body break down.

The brain regulates body temperature. The control center is the hypothalamus, which monitors temperature signals from internal organs, as well as the skin, limbs and blood. It sends out electrical and chemical signals to sweat glands, muscles, blood vessels and endocrine glands, telling the body how best to adjust to shifts in temperature.

The body's goal is to achieve an internal temperature as close as possible to 98.6 degrees Fahrenheit. That's not hard if the external temperature is below that. When it is higher, the hypothalamus alerts the body, stimulating sweat glands and dilating blood vessels in the skin.

Profuse sweating then begins, the first step of overheating. While a little or even moderate sweating may be beneficial because it cools the body, profuse sweating can lead to salt imbalance and dehydration.

Excessive sweating causes the body to shrivel from lack of fluids: Blood pressure drops, and sodium, potassium and chloride are all depleted as the body's finely tuned mechanisms for regulating temperature and cooling start to malfunction.

The first sign that something is wrong may be the development of heat cramps, which are most commonly seen in athletes who work out too strenuously in hot weather. Heat cramps are eminently treatable, usually by drinking slightly salted water that restores fluids and salts.

The next and more serious stage is heat exhaustion, which often occurs among people not used to high heat. Heat cramps may be present; the skin appears pale and clammy, breathing is fast and shallow, like a dog's panting, and some victims faint or vomit. Disorientation and confusion is common.

Heat exhaustion is not hard to treat - it typically involves lying with the feet slightly elevated in a cool place and drinking a salt water solution. Heat exhaustion requires immediate medical attention primarily so doctors can ensure that the most serious form of heat-related illness, heatstroke, has not occurred.

The line between heat exhaustion and heatstroke is not well-defined, Milzman says, and the progression from a serious problem to the medical emergency of heatstroke can occur within minutes.

Heatstroke, a major risk in conditions of extreme heat and high humidity, is typically caused by prolonged exposure. It is more likely to befall elderly people in poor health and those who are taking drugs that retard sweating. One such class of drugs is anticholinergic medications used to treat Parkinson's disease, asthma and urinary incontinence. Alcohol, which speeds dehydration, can also help precipitate heatstroke. Sufferers may stop sweating as their body temperature rises. The skin becomes hot and dry, the pulse is fast and weak, and victims may lapse into unconsciousness.

Victims of heatstroke need immediate medical attention; their body temperature must be reduced quickly. This is often accomplished by removing all clothing and wrapping a victim in cold, wet sheets. If it is treated fast enough, most victims recover. If not, damage to organs and cells is simply too overwhelming and death results.

One problem, Milzman said, is that there is no magic temperature that represents a true danger. ``It's different for different people who have different pre-existing disease states.''