The science, in plain English · June 2026
Does the sauna really
help you live longer?
Here is a claim that floats around the internet a lot: sitting in a hot room a few times a week will help you live longer. Normally a claim like this resolves, on inspection, into a guy selling a supplement. This one is different, mostly because it traces back to two large, patient, genuinely well-run studies out of Finland (a country with strong feelings about saunas) — one from 2015 that followed 2,315 men for about 20 years, and one from 2018 that added women. So they are worth actually reading: what they found, and the catch the headlines reliably leave out. Every number here comes straight from the papers.
First, one bit of jargon
What “a lower risk” actually means here
One piece of setup to get straight first, because it is the exact spot where claims like this go wrong. Every number below is a comparison between two groups of people: the ones who used the sauna a lot, and the ones who used it just once a week. The once-a-week people are the baseline. Everyone else gets measured against them.
So when a study says “about 50% lower,” what it means is that the frequent-sauna group was roughly half as likely to die of some specific cause, across the years of the study, as the once-a-week group. That is a fact about two groups of Finns. It is not a fact about you, and it is very much not a promise. The whole back half of this page leans on that difference, so it is worth banking now.
(The technical term for this comparison is a “hazard ratio,” which sounds scarier than it is. Everything here is in plain “% lower” wording, with the exact figures one click away in the sources, for the sort of reader who likes to check.)
The 2015 study · 2,315 men, 20.7 years
The study that started it all.
Start with the one everyone cites. Researchers in eastern Finland took 2,315 middle-aged men, ages 42 to 60, asked each one how often he used the sauna and for how long, and then did the slightly grim thing this kind of study requires, which is wait about 20 years to see who died. The habits were not exotic. A typical visit was about 14 minutes at around 79°C. Nobody was assigned a regimen; these are just Finnish men being Finnish.
And the result is the kind that keeps a study cited for a decade. The more often a man used the sauna, the lower his risk of dying over those 20 years, and the pattern held up even after the researchers adjusted for the usual suspects — age, weight, blood pressure, smoking, fitness. The table puts the few-times-a-week men and the almost-daily men next to the once-a-week group.
| Risk of… (compared with going once a week) | Going 2–3×a week | Going 4–7×a week |
|---|---|---|
| Sudden cardiac deathThe heart suddenly stops | about 22% lower(could be chance*) | about 63% lower |
| Fatal coronary heart diseaseDeath from clogged heart arteries | about 23% lower | about 48% lower |
| Fatal heart & blood-vessel diseaseDeath from any heart or circulation cause | about 27% lower | about 50% lower |
| Death from any causeDying of anything at all | about 24% lower | about 40% lower |
*Every other figure in this table was statistically solid. The one marked “could be chance” was too uncertain for the researchers to be confident it wasn't a fluke, so we're flagging it rather than dressing it up. Source: Laukkanen et al., JAMA Internal Medicine, 2015.
Length of each visit told the same story. Men who sat past about 19 minutes had roughly half the sudden-cardiac-death risk of men who tapped out under 11. And this is the detail that matters more than any single row of the table: it is a dose-response. More sauna, less risk, stepwise, in order. A dose-response is the closest thing epidemiology has to the data quietly clearing its throat and saying “this might be real” — because random noise does not, as a rule, bother to line itself up so neatly.
The 2018 study · 1,688 people, 51.4% women
The follow-up that included women.
There is an obvious hole in that first study, and you have probably already found it: it was 2,315 men and no women at all. So in 2018 the same group ran it back, this time with 1,688 people aged 53 to 74, just over half of them women, followed for about 15 years. Same corner of Finland, same sauna-saturated culture, the missing half of the population finally invited.
The cleanest way to see what came back: line up 1,000 people, watch them for a year, and count the heart-related deaths. In the once-a-week group, about 10 of the 1,000 died. In the almost-daily group, fewer than 3 did. Same year, same kind of people, a third as many deaths in the group that used the sauna most.
Once a week
~10
heart-related deaths per 1,000 people each year
2–3 times a week
~8
heart-related deaths per 1,000 people each year
4–7 times a week
~3
heart-related deaths per 1,000 people each year
In percentage terms, the near-daily group carried roughly a 77% lower rate of heart-related death than the once-a-week group. And the benefit never hit a ceiling and stopped — every step up in frequency bought another step down in risk, the whole way along. That steady downhill staircase is the reassuring part, because one spectacular number is easy to fluke into and a tidy staircase is not.
Two more things fell out of the numbers. Total time mattered: people who logged more than about 45 minutes a week did better than people under 15. And sauna frequency told the researchers something about a person's heart risk that the usual suspects (blood pressure, cholesterol, smoking) had not already accounted for. Which is to say the sauna number was pulling its own statistical weight, not just standing in for “this person is generally healthy.”
Source: Laukkanen et al., BMC Medicine, 2018 (also listed on PubMed). Exact figures are in the paper.
Men vs. women
Is it different for men and women?
Short version: no. The studies do not point to a different sauna routine for women than for men. The 2018 researchers actually ran the statistical test for this (does the effect change by sex?) and the answer came back no, the pattern runs the same direction for both. So if someone is selling you a special “women's sauna protocol,” that is a marketing decision, not a finding from this data.
For men
The fuller picture.
Men have been studied the longest and in the most detail — that whole first study, 2,315 of them over 20 years. The frequent sauna-users had lower rates of every heart-related cause the researchers looked at, plus a lower chance of dying from any cause at all. It's the strongest version of the evidence.
For women
Same direction, newer evidence.
Women only entered the picture in 2018, so the evidence is newer and thinner. Here is the funny statistical problem: among the women who used the sauna most often, essentially nobody died of heart-related causes during the study. Which is great if you're one of those women, and mildly annoying if you're trying to compute an exact risk number, because you cannot do much math with zero.
So the summary is boring in the good way: the same habit lined up with a longer, healthier life for both men and women. The men's evidence is just deeper, because it has had more years to pile up.
The part the headlines skip
The honest catch.
Now the part where most coverage of these studies quietly falls apart. As good as the papers are (and they are good, which is the whole reason anyone cites them), they cannot prove the sauna caused the longer lives. They can show that sauna use and living longer travel together. They cannot show that one is driving the other. That sounds like hair-splitting and it is absolutely not, for a few reasons:
- Nobody ran the actual experiment. An experiment would mean grabbing people, randomly ordering half of them into the sauna and half onto the couch, and waiting. That never happened. These studies watched what people already did, which is cheaper and more ethical and also weaker.
- Healthy people are the ones who can sauna a lot. Sitting in 80°C heat four times a week is, itself, a thing that healthy people can do and sick people often can't. So the frequent-sauna group may have been healthier to start with, and the sauna gets the credit. The researchers adjusted for what they could measure, but “adjusted for” is not “eliminated.”
- Everyone got asked about their habits exactly once. At the start. Then the studies ran for 15 to 20 years, during which people presumably changed, the way people do, and nobody checked back in.
- This is one very specific kind of sauna. Dry, hot, around 80°C, water on the rocks, the traditional Finnish setup. The authors are explicit that the findings don't automatically transfer to other heat — which very much includes the cooler infrared cabin sitting in someone's garage at 55°C.
- And it is all one corner of one country. Eastern Finland, where the sauna is not a wellness purchase but a lifelong cultural default. Whether the same thing holds in a place that treats saunas as exotic is, so far, an open question.
None of which means the sauna doesn't work. It means what these studies deliver is a strong, consistent link, not proof — and a strong link is genuinely a useful thing to know, as long as nobody quietly upgrades it to a guarantee on the way to selling you something.
From cohort to practice
So what do you actually do with this?
Here is the reasonable read. The data is not strong enough to promise anybody anything. It is, however, more than strong enough that if you already enjoy the sauna, going regularly is an easy call with a genuine upside attached. And if you're going to copy a routine, the obvious one to copy is whatever the people in these studies were actually doing. It's the same for men and women, because, again, the research never found a reason to split them.
What the healthiest sauna-users in the studies did
- How often: 4 to 7 times a week. This is where the lowest risk showed up. Going 2–3 times still looked good, just less dramatically so.
- How long each time: around 15 to 20 minutes a session.
- Total per week: more than about 45 minutes added up across the week.
- How hot: a proper hot, dry Finnish-style sauna, roughly 80°C. Not the gentler infrared cabins, which weren't what these studies measured.
One caveat that does not get skipped: talk to a doctor first if you have a heart condition, are pregnant, run low blood pressure, or take anything that changes how your body handles heat. This is exactly the kind of place where the average across 2,000 Finns stops being a fact about you.
One last move worth stealing from the researchers: they never judged a single sauna session. They watched what happened over years. That is the entire idea behind Sauna Score, which watches how your own body responds across weeks of regular use versus quieter weeks, using the data your phone or watch already collects, and which says so plainly when there isn't enough yet to call. If you're comparing apps, there's also a writeup of the best sauna apps of 2026.
FAQ
Sauna and longevity — common questions.
Does the sauna actually help you live longer?show
The honest answer: these studies show a strong link, not final proof. Men who used the sauna 4–7 times a week were about 40% less likely to die from any cause over the 20 years of the study than men who went once a week. That's a big, consistent difference — but because no one ran a true experiment, we can't be 100% sure the sauna is what caused it rather than, say, those people being healthier to begin with.
How often should you use the sauna?show
In both studies, the lowest risk showed up in people who went 4 to 7 times a week. Going 2–3 times a week still looked good, just less strongly. And there was no point where 'too much' became a problem — the more often people went, the lower their risk tended to be.
How long should each session be?show
The people in these studies typically spent about 15 to 20 minutes per visit, and aimed for more than roughly 45 minutes total across the week. Longer individual sessions (over about 19 minutes) lined up with the lowest risk.
Is the benefit different for men and women?show
The research doesn't point to a different routine for each. Men were studied longer and in more detail, so their evidence is fuller. Women were added in the 2018 study, and the benefit ran in the same direction — encouragingly, almost none of the women who used the sauna most often died of heart-related causes during the study. So the same habit looks good for both.
Do infrared saunas count?show
We don't really know. These studies all used the traditional hot, dry Finnish sauna — around 80°C, with water thrown on the rocks. Infrared cabins run a lot cooler (often 45–60°C), and the researchers were clear that their findings don't automatically apply to other types of heat. It might help; it just wasn't what was tested.
Is this proof that the sauna causes a longer life?show
No — and the researchers don't claim it is. What makes it worth taking seriously: the benefit grew the more often people went, the studies followed people for 15 to 20 years, and the researchers adjusted for things like fitness, smoking, and blood pressure. What keeps it short of proof: healthier people may simply sauna more, habits were only measured once, and it's all from one part of Finland. Both sides of that are right there in the papers.
A note on what this isn't
This page is informational — a review of published cohort research, not medical advice, diagnosis, or treatment. The studies describe associations observed in a population; they do not promise you a personal outcome. If you have a cardiac condition, are pregnant, have low blood pressure, or take medication affecting thermoregulation, talk to your doctor before any sauna or cold-exposure practice.
See if the sauna is working
for your body.
Sauna Score watches how your sleep, heart rate, and recovery respond over weeks of regular sauna use, using the data your phone or watch already collects, and it tells you plainly when it's too soon to say.