About 75 million American adults—just one in three—suffer from hypertension, or high blood pressure, according to the Centers for Disease Control and Prevention (CDC). High blood pressure simply means that the force with which the blood surges through the arteries is too high, but this simple problem can have deadly consequences. Paired with other factors, high blood pressure can lead to stroke, heart disease, heart attacks and numerous other problems. However, a recent study from Finland found that frequent sauna baths could cut the risk of hypertension in half in middle-aged men, compared with their contemporaries who use the sauna less frequently.
The study looked at the long-term blood pressure of 1,600 middle-aged men in Finland who were determined to have high blood pressure, or blood pressure at or above 140/90. The men were divided into three groups: those who used the sauna once per week, those who went two to three times per week, and those who went four to seven times per week. Over a median follow-up period of 24.7 years, the researchers tracked the blood pressure of the men, and found that the ones who used the sauna four to seven times per week were at half the risk of those who used it once a week. Yes, half.
There are a number of factors that could explain this. This is certainly a direct correlation, as those who used the sauna two to three times per week were at a 24 percent lower risk of developing high blood pressure than those who only used it once per week, and those who went four to seven times were at a 46 percent lower risk. However, this does not necessarily imply causation, as further research would have to be conducted to prove that it is a direct cause.
Still, these numbers make sense. One explanation suggested by the team is that the increase in body temperature that happens in a sauna causes the arteries to dilate, thereby decreasing blood pressure. They also suggested that it may improve the function of the lining tissues of arteries, or endothelium, also decreasing blood pressure. Furthermore, the sauna causes you to sweat, which releases fluids from the body and relaxes both the body and mind, which could also contribute to the decrease in long-term blood pressure.