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

The study, in the American Journal of Hypertension, 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 percent less likely to have hypertension, and four to seven visits a week reduced the risk by 46 percent. The study controlled for body mass index, alcohol consumption, resting heart rate, smoking, family history of hypertension and other variables.

The study is observational and does not prove cause and effect, but the senior author, Dr. Jari A. 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 eases blood flow, and the warmth and subsequent cooling down of a typical Finnish sauna induces a 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.

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