Heatstroke: Who's at Risk

by Food and Drug Administration (FDA)

(Page 2 of 2)

Certain health conditions increase a person's risk of heat illness. Obesity, sweat gland diseases, diabetes, dehydration (a shortage of body fluids), malnutrition, low blood pressure, and heart disease all make it difficult for the body to regulate heat. In many instances, patients have more than one of these conditions. Older adults, especially, are more likely to have multiple health problems.

Older adults also are more likely to take medicines that impair the body's ability to regulate heat. Some drugs slow sweat production. These include anticholinergics (used to treat Parkinson's disease), antihistamines (for allergies), phenothiazines (tranquilizers), tricyclic antidepressants, and diuretics (for high blood pressure). Some restrict blood flow to the skin, impairing the body's ability to release heat. These include cardiovascular drugs, such as vasoconstrictors and beta blockers.

If you or someone you know lives without air conditioning and takes any of these medicines, ask a doctor or pharmacist about the medicine's possible ill effects in hot weather.

Also at risk are people who use illicit drugs, such as LSD, cocaine and amphetamines. These drugs increase muscle activity and body heat. Excessive alcohol use greatly increases a person's risk for heat illness, too. Alcohol causes the body to excrete water, leading to dehydration.

People who are unable to move about easily — for example, disabled, homeless, and very poor people — are at a higher risk for heat illness because they often cannot afford air conditioning or get to a place that has it. Also, children under 2 can be prone to heat illness because their small bodies cannot regulate body heat as efficiently as older children or adults can. They also may not be able to escape hot places; every summer there are tragic reports of young children who die of heatstroke because they are left in locked automobiles even for short periods.

A victim of heat exhaustion or heatstroke needs immediate medical attention. The important thing is speed: The faster the victim is cooled and rehydrated, the better his or her chance for survival.

Says FDA's Koller, "If people have heatstroke, they really need to get care quickly. This is truly a medical emergency."

Preventing Heatstroke

"... At harvest time, the boy went out one morning to join his father, who was in the field with the harvest workers. Suddenly he cried out to his father, 'My head hurts! My head hurts!' ... The servant carried the boy back to his mother, who held him in her lap until ... he died."

— 2 Kings 4:18-20

In what may be one of the oldest accounts of heatstroke, the Bible tells of this ailment's deadly end. Luckily for the boy, the prophet Elisha was near, and the scripture recounts a miraculous rising from the dead.

It's still possible to survive heatstroke, but it's far easier to prevent it. Here's how:

Take it easy, especially if you are over 65, on any heart or blood medication, or are overweight. Don't make any changes with your medications without your doctor's OK. Don't exert yourself in the summer heat. Exercise in an air-conditioned building if possible.

If you exercise outdoors in the summer, do so in the early morning or late evening hours when it's cooler.

Get used to hot weather slowly. When exercising or doing some other activity outdoors in hot weather, start slowly and gradually increase the time each day. Studies have shown that getting used to the hot weather gradually increases the body's ability to sweat freely without losing salts. It takes about two to four weeks of exercising in the heat before you'll become acclimatized.

Drink lots of water in the summer. If you're exercising, that means about 1 liter (about 1 quart) every hour. If you're just puttering in the garden, take a large jug of water with you, and sip it continuously. Don't rely on thirst to tell you when to drink; people often don't feel thirsty until they're a little dehydrated. Sports drinks and special rehydration fluids are OK, but studies have shown that water alone, combined with a normal amount of dietary salt prevents dehydration in most people. Do not take salt tablets, unless advised to by a doctor, because the excess amount of sodium in them can increase the risk of kidney damage.

Wear a hat with a broad brim to protect you from the sun and loose clothing to allow sweat to evaporate.

Wear sunscreen. A sunburn will inhibit your skin's ability to sweat.

Stay in an air-conditioned environment on hot days. If that's not possible, take cool baths, spray yourself with water frequently, and sit in front of a fan. If you feel faint, call for emergency medical attention.

Heatstroke Risk

In hot weather, these factors can put you at risk for heatstroke:

• exercise, especially if you're not physically fit
• heavy clothing
• living on upper floors of a building without air-conditioning
• not drinking enough fluids, leading to dehydration (shortage of body fluids)
• drinking too much alcohol
• obesity
• tiredness
• older age (65 and over)
• high outdoor humidity
• lack of wind
• medical conditions — including alcoholism, neurologic lesions, cardiovascular disease, skin or sweat gland diseases that inhibit the skin's ability to sweat, diabetes, chronic obstructive pulmonary disease, hyperthyroidism, hypokalemia (potassium deficiency), infections that cause fever, and taking certain medications for psychiatric illnesses.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.