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Sauna safe for most healthy folks

TUESDAY, JULY 24, 2012

DEAR DOCTOR K: I love saunas, but my wife worries they’re dangerous. Is she right?

DEAR READER: Many cultures use heat for relaxation and therapy. One of the oldest – and hottest – of these techniques is the sauna.

The modern sauna is a simple, unpainted room with wooden walls and benches. A rock-filled electric heater keeps the temperature at about 90 degrees at floor level and boosts it to about 185 degrees at the top. Saunas are very dry; humidity levels are just 10 percent to 20 percent. A good sauna is also well-ventilated.

The dry heat has profound effects on the body. The average person loses a pint of sweat during a brief sauna. Skin temperature soars to about 104 degrees, though internal body temperature usually stays below 100 degrees.

Your heart responds to this dry heat as well. Your pulse rate jumps by 30 percent or more. As a result, your heart nearly doubles the amount of blood it pumps each minute. Blood pressure may rise or fall. So although a sauna may help your muscles and your attitude to relax, your heart is working hard while you sit on your bench. Is that safe?

Research suggests that it is. Saunas do not increase the risk of heart attack in healthy people. And saunas even appear to be safe for patients with stable coronary artery disease – atherosclerosis, or cholesterol-filled plaques in the arteries of the heart.

If you have any heart problems, the safest thing is to check with your doctor before using a sauna.

To play it extra-safe, follow these simple precautions:

• Avoid alcohol before or after your sauna.

• Limit your sauna to 15 to 20 minutes.

• Cool down gradually afterward.

• Drink two to four glasses of cool water after each sauna.

• Don’t take a sauna when you are ill.

Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.

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