You probably know the heavy, pleasant tiredness that follows a long, hot bath or an evening at the sauna. The muscles let go, the shoulders drop, and the day feels further away. That same heat may be doing more for your heart than it feels like.
Men who went to the sauna four to seven times a week had a 63 percent lower risk of sudden cardiac death than men who went only once a week. That is according to a 20-year Finnish cohort study of 2,315 middle-aged men, published in JAMA Internal Medicine in 2015.
Risk of dying from any cardiovascular disease was 50 percent lower in the frequent-use group. Men who went two or three times a week sat in the middle, with a 27 percent lower risk of fatal cardiovascular disease. All-cause death dropped by 40 percent in frequent users.
Longer sessions pointed in the same direction
Session length mattered too. Men whose typical visit lasted more than 19 minutes had about half the risk of sudden cardiac death, compared with those who stayed under 11 minutes.
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Finnish saunas typically run at 80 to 100 degrees Celsius at face level, the study authors noted.
The research followed men aged 42 to 60 for a median of about 21 years. All the participants were men, which limits how directly the numbers apply to women.
The study is observational, so it points to a strong association, not proof that the sauna itself caused the lower risk. Lifestyle factors in a country with ingrained sauna culture likely play a role too.
Heat therapy is becoming its own research field
The findings have drawn renewed attention this autumn. A small group of scientists met at The Well resort outside Oslo in late September 2026 to standardize how heat therapy is studied.
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Public radio station KETR reported that about 15 researchers attended the first International Heat Therapy Research Symposium.
Ashley Mason, a clinical psychologist at the University of California San Francisco, told KETR that the field is trying to move past its old reputation. "We want to introduce this as an actual field of research, not something fringy, or woo-woo," she said.
Ant Shepherd's lab at the University of Portsmouth has studied hot tub use. Time in a hot tub improved resting metabolic rate and some markers of insulin sensitivity in people with type 2 diabetes.
Earlier research also suggested that regular sauna use may protect the heart about as well as moderate exercise.
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Researchers caution that firm, personalized advice is not yet in reach. "People want information," Earric Lee, a postdoctoral researcher at the Montreal Heart Institute, told KETR. "But I really can't give you recommendations, and that's the honest truth of it."
Readers with heart conditions, low blood pressure or who are pregnant should check with their doctor before starting regular sauna sessions.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.