A study suggests that regular sauna visits can reduce the risk for high blood pressure.

Published in the American Journal of Hypertension, the study included 1,621 middle-aged men with normal blood pressure who were followed for an average of 25 years. During that time, 251 developed hypertension.

Compared to those who reported one sauna session a week or less, those who took two to three sessions were 24 per cent less likely to have hypertension, and four to seven visits a week reduced the risk by 46 per cent.

The study controlled for body mass index, alcohol consumption, resting heart rate, smoking, family history of hypertension and other variables.

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The study is observational and does not prove cause and effect. But the senior author, Dr. Jari Laukkanen, a professor of medicine at the University of Eastern Finland, suggested several possible mechanisms.

The warmth of the sauna, he said, improves the flexibility of the blood vessels which then eases blood flow. Sauna bathing can increase body temperature by up to 2 degrees Celsius (about 3.5 degrees Fahrenheit). This can cause blood vessels to dilate, or become wider, decreasing blood pressure and helping blood flow easier, he says. Sauna bathing can also increase resting heart rate to 100 to 150 beats per minute, he says (up from the average 60 to 100 beats, according to the American Heart Association), improving pumping power.

The warmth and subsequent cooling down of a typical Finnish sauna, which are between 176 and 212 degrees Fahrenheit, can induce general relaxation that is helpful in moderating blood pressure.

Also, sweating removes excess fluid, acting as a natural diuretic. Diuretics are among the oldest drugs used to treat hypertension. Plus, the authors say, spending time in the sauna likely helps people relax—both physically and mentally—and may protect against the harmful effects of stress.

“This is good news,” he said. “A healthy thing that is pleasant to do and involves no sacrifice.”

The authors point out that their findings may not apply to other types of saunas, steam rooms or hot tubs that may operate at lower temperatures. And even though it controlled for a variety of influencing factors, the study was only able to show an association between sauna frequency and blood pressure—not a cause-and-effect relationship.

More studies are needed to see if the blood-pressure benefits of sauna bathing translate to other people, including women and people who aren’t regular sauna users. But overall, the authors write that “sauna bathing, an activity that promotes relaxation and well-being, may be a recommendable habit in the prevention of future hypertension.”/.

VNF/NYT