You may have seen news reports last year about studies linking sauna use to a variety of health benefits. Before you start shvitzing in a sauna at a spa or health club, you should know that the research is limited and mostly comes from Finland, where saunas are part of the national culture and are found in most homes and even offices. A typical Finnish sauna is a wood-paneled room with an electric heater containing rocks, over which you ladle water to increase the humidity. The temperature is usually at least 150°F.
Most of these Finnish studies have used observational data from the all-male Kuopio Ischemic Heart Disease Risk Factor Study, which recorded, among many other things, whether and how often the middle-aged men used saunas over a two-decade period (women were added after the first decade).
- One study, in the American Journal of Hypertension in 2017, found that men who most often used saunas had a reduced risk of developing hypertension. The researchers hypothesized that saunas may reduce blood pressure by promoting relaxation and by improving blood vessel flexibility. This was supported by a small clinical trial in the European Journal of Preventive Cardiology in 2017, which found that middle-aged Finnish men and women had reductions in blood pressure and blood vessel stiffness after spending 20 minutes in a sauna.
- Two other Finnish studies from 2017 linked frequent sauna use (four or more times a week) to reduced risk of pneumonia or Alzheimer’s disease.
- Most impressive, an analysis in JAMA Internal Medicine in 2015 found that Finnish men who used saunas four to seven times a week over the two decades had significantly lower cardiovascular and all-cause mortality rates than men who used them infrequently.
- The most recent study, in Neurology in 2018, found that Finnish men and women who used saunas four to seven times a week had a merkedly reduced risk of stroke compared to those who rarely used them. However, sauna use two or three times a week did not reduce the risk.
- In a small Polish study from 2014, young men who had 10 sauna visits over three weeks had modest reductions and total and LDL (“bad”) cholesterol. There was no comparison group, however.
Caveats and questions
Keep in mind that since most of these were observational studies, they can only find associations between sauna use and various health outcomes, not establish causality. There may be something else about people who are able to sit in saunas for hours every week that helps keep them healthy, though the researchers controlled for many confounding factors. And since most of the studies involved middle-aged Finnish people (usually men), it’s not known if the results would also occur in other people—and in those who use saunas less frequently than the Finns do.
Would steam rooms and hot tubs have the same potential benefits as saunas? That’s also unknown, since there has been much less research on them.
Bottom line: Use a sauna only if you find it relaxing and enjoyable, not as a health cure or as a substitute for exercise. If you’re a novice, start with short visits at moderate temperature. Drink plenty of water, and avoid alcohol. Avoid saunas, or at least check with your doctor before using one, if you are pregnant, have heart disease or another medical condition, or are taking medication that may affect blood pressure. If you become lightheaded, leave the sauna.
Also see Infrared Saunas.
Originally published January 2018.