Sauna Bathing and Sudden Cardiac Death: What a 20-Year Finnish Study Found

Of all the observational research linking sauna use to heart health, this is the single most-cited study in the field — a two-decade tracking of Finnish men that established the dose-response relationship between sauna frequency and fatal cardiac events.

What the research looked at

Published in JAMA Internal Medicine in 2015, this prospective cohort study followed 2,315 middle-aged men from eastern Finland for an average of 20 years as part of the Kuopio Ischaemic Heart Disease Risk Factor Study. At baseline, participants reported how often and how long they used a traditional Finnish sauna. Researchers then grouped them into three categories — once a week, two to three times a week, and four to seven times a week — and tracked deaths from sudden cardiac death, fatal coronary heart disease, fatal cardiovascular disease, and any cause.

What they found

Compared with men who used the sauna once a week, those who went four to seven times a week had a 63% lower risk of sudden cardiac death, a 48% lower risk of fatal coronary heart disease, and a 50% lower risk of fatal cardiovascular disease. All-cause mortality was 40% lower in the most frequent sauna users. Longer sessions mattered too — sessions over 19 minutes were associated with a 52% lower risk of sudden cardiac death than shorter ones.

What this means in practice

This is an observational study, not a randomized trial — it shows a strong, consistent association, not proof that sauna use itself caused the lower risk, and the authors note that healthier men may simply be more likely to sauna often. It's also specific to traditional Finnish dry sauna in Finnish men, so the exact numbers may not transfer directly to infrared saunas or other populations. Still, it's the most robust, longest-running dataset connecting sauna frequency to heart health, and it's part of why cardiologists increasingly view regular sauna use as a reasonable complement to — not a replacement for — standard cardiovascular care.