Sauna and longevity: can it help you live longer?

"Sauna linked to longer life" is one of those headlines that comes round every year or two. It traces back to a real and well-run Finnish study. What the study can and can't tell you is worth a few minutes before you plan your week around it.

The study behind the headlines

In February 2015, JAMA Internal Medicine published a paper from the Kuopio Ischaemic Heart Disease Risk Factor Study, a long-running project in eastern Finland. Between 1984 and 1989, 2,315 men aged 42 to 60 had a thorough health check and answered questions about their habits, including how often and how long they used the sauna. Researchers then followed them for a median of 20.7 years.

By the end, 929 of the men had died. The researchers compared three groups: men who used the sauna once a week (601 of them), 2–3 times a week (1,513) and 4–7 times a week (201). Nobody in the study went less than once a week, which says a lot about Finland.

What it found

Start with the raw numbers, before any statistics. During the follow-up, about 49% of the once-a-week men died, compared with 38% of the 2–3 times group and 31% of the 4–7 times group.

The researchers then adjusted for known risk factors, such as blood pressure, cholesterol and smoking. Compared with the once-a-week group:

• 2–3 sessions a week was linked to a 24% lower risk of death from any cause
• 4–7 sessions a week was linked to a 40% lower risk

The links with heart deaths were stronger still: a 63% lower risk of sudden cardiac death in the most frequent group. Our guide to sauna and heart health goes through those numbers.

One detail often gets left out. Longer sessions, over 19 minutes, were linked to fewer heart deaths, but not to fewer deaths overall. So the study doesn't support sitting in the heat for longer to live longer. How often people went seemed to matter more.

What "linked to" means

This was an observational study. The researchers didn't tell anyone how often to use the sauna. They recorded what people already did and saw who lived longer. That leaves room for other explanations:

• Healthy people may go more often. If you're already unwell, a daily sauna is the kind of habit you drop.
• Time and money. A sauna every day can mean a home sauna, more free time and less stress. Later analyses of the same men adjusted for income, but not everything can be measured.
• Company. In Finland, a sauna is often shared with family or friends. That's hard to separate from the heat itself.

Also, "40% lower risk" doesn't mean you'll live 40% longer. It means that over those two decades, a frequent sauna user's chance of dying at any given point was around 40% lower than a weekly user's, after the adjustments. It's a relative figure, and on its own it doesn't tell you how many extra years that adds up to.

Only a randomised trial, with people assigned to sauna or no sauna for many years, could prove cause and effect. Nobody has run one, and it would be very hard to do.

Other studies that point the same way

One study is easy to dismiss. Several studies pointing the same way are harder to ignore:

• Men and women. A 2018 study in BMC Medicine of 1,688 people aged 53 to 74 in eastern Finland, just over half of them women, found that deaths from heart and circulation disease fell as sauna use went up.
• Stroke and dementia. Frequent sauna users in the Kuopio research also had lower rates of stroke and dementia. See sauna and dementia risk.
• Japanese baths. A 2020 study in the journal Heart followed 30,076 Japanese adults aged 40 to 59. People who took a hot tub bath almost every day had a 28% lower risk of heart disease and stroke than those who bathed twice a week or less. It's a different kind of heat, but the pattern is similar.

All of these are observational too, and most come from the same Finnish research group. They make the link more convincing, but they don't settle the question.

Sauna and the rest of your habits

A 2018 analysis of the Kuopio men looked at fitness and sauna use together, measuring fitness in a lab exercise test rather than by asking. Compared with men who were unfit and used the sauna twice a week or less, men who were both fit and used the sauna 3–7 times a week had a 69% lower risk of sudden cardiac death. Fitness alone was linked to a 51% lower risk.

The takeaway is simple. The sauna seems to add to the benefits of being active. It doesn't replace them. Not smoking, moving every day, sleeping well and keeping your blood pressure in check still do the heavy lifting.

If you want to copy the habit

• Frequency first. The clearest results were in people who went at least 2–3 times a week.
• A proper hot sauna. The studies looked at traditional Finnish saunas, usually around 80 °C (176 °F). Our sauna temperature guide explains the ranges.
• Moderate rounds. 10–20 minutes at a time, with breaks to cool down. Longer isn't better.
• Go with people you like. It won't hurt.

For the full rundown of what the research says, see sauna benefits.

Who should be careful

For most healthy adults, regular sauna use is very safe. Check with a doctor first if you have heart disease, unstable or very high blood pressure, or have recently had a heart attack or stroke, if you are pregnant, or if you take medicine that affects blood pressure. Never use a sauna after drinking alcohol, and leave if you feel dizzy, sick or confused.

This guide is general information, not medical advice.

Where to find a traditional sauna

Find My Sauna lists 2,616 places with a Finnish-style sauna. These cities have the most:

Tallinna Saun

Tallinn · Textile-free sauna

Saunasaari

Helsinki · Finnish sauna

Lemonranta (Ala-Lemun kartano)

Turku · Outdoor sauna

Frequently asked questions