Is a sauna good for you?
It may be, if you’re healthy. Finnish men who took 4 to 7 saunas a week had fewer fatal heart problems than men who went once. But the weight you lose in there isn’t fat.
On this page
Is a sauna good for you?
It may be. The best evidence comes from a Finnish study of 2,315 men aged 42 to 60, followed for about 20 years.
Men who took 4 to 7 saunas a week were less likely to die suddenly from a heart problem than men who went once. After allowing for other heart risks, their risk was 63% lower.
| Saunas a week | Died suddenly from a heart problem | Died from any cause |
|---|---|---|
| Once | 10.1% | 49.1% |
| 2 to 3 | 7.8% | 37.8% |
| 4 to 7 | 5.0% | 30.8% |
Source: Laukkanen 2015, JAMA Intern Med
This study watched what men already did. It didn’t give anyone a sauna, so it shows a link, not proof. Men who went often may have differed in other ways.
All the men were Finnish, and none were women. If you’re healthy and enjoy a sauna, the sections below show how to use one safely.
What are the health benefits of a sauna?
The same group of Finnish men gives the three biggest findings. Each compares 4 to 7 saunas a week with one.
| Health problem | What the study found | Who was studied |
|---|---|---|
| High blood pressure | 46% less likely to develop it. | 1,621 Finnish men aged 42 to 60 without high blood pressure at the start |
| Dementia | 66% less likely to be diagnosed with it. | 2,315 Finnish men aged 42 to 60 |
| Sudden death from a heart problem | 63% less likely. | 2,315 Finnish men aged 42 to 60 |
Sources: Zaccardi 2017; Laukkanen 2017; Laukkanen 2015
A review of 40 sauna studies found most reported benefits. But only 13 were proper trials, and most had fewer than 40 people.
Its verdict: regular dry saunas have potential health benefits. A second review says saunas may be linked to lower blood pressure. That’s a maybe, not a yes.
So treat a sauna as a pleasant extra, not a fix. To know where you stand now, check what a normal blood pressure is.
Does a sauna help you lose weight?
Not in a way that lasts.
A study had 674 students aged 19 to 20 sit in a dry sauna for 20 minutes. On average, the slimmest women lost about 0.24 kg. The heaviest men lost about 0.82 kg.
That weight is sweat. About 1 kg of weight lost is 1 litre of sweat, and it comes back when you drink.
Source: Podstawski 2014
The higher your BMI (your weight measured against your height), the more you tend to sweat out. The researchers say to drink during and straight after each session.
Sauna venues often claim to detox you or speed up your metabolism. The review calls the evidence for such claims scant and incomplete. To lose fat, see the best exercise for weight loss.
How hot is a sauna, and how long should you stay in?
A traditional Finnish sauna is the hottest kind in the studies. An infrared sauna runs much cooler.
| Type | How hot | What it’s like |
|---|---|---|
| Traditional Finnish | 80°C to 100°C | Dry air (10% to 20% humidity). |
| Infrared | 45°C to 60°C | Uses infrared heaters, with no water or added humidity. |
| Steam room | Not in the review | Very humid air. Left out of the dry sauna studies. |
Source: Hussain and Cohen 2018
A Russian banya and a Turkish hammam are other traditional styles of hot bath. The findings above come from dry saunas, so they may not apply.
Finnish sessions usually last 5 to 20 minutes. The review found too little evidence to say how hot, how long or how often is best.
So start short. Get out if you feel dizzy, tired or sick, get a headache or cramps, or your skin turns pale and clammy. Those can be signs of heat exhaustion.
Is a sauna safe?
Deaths are rare. Sweden and Finland recorded 0.06 and 2 sauna deaths a year for every 100,000 people.
Half or more of those deaths involved alcohol, and being alone in the sauna was common. Keep an eye on how much you drink each week too.
Safer sauna habits
- Skip alcohol before and during a sauna, and don’t go in on your own.
- Drink water during and straight after each session.
- Start with short sessions. The review found too little evidence to say how hot, how long or how often is best.
- Get out if you feel dizzy or sick, or get a headache.
- Have a heart condition? Ask your GP or heart team before you start.
- Pregnant? Ask your midwife before using a sauna.
Sources: Hussain and Cohen 2018; Podstawski 2014; NHS
Why the heart check? Saunas have been linked to the heart muscle running short of blood, especially in people whose heart disease is unstable.
Trying for a baby? In one small study, 3 months of saunas lowered sperm count. It recovered after the men stopped.
The NHS says warmer testicles may affect sperm quality. See male fertility tests.
Pregnant? The NHS says to stop exercise if you feel too hot. The same care makes sense in a sauna, so check with your midwife first.
When to speak to a GP
Heat exhaustion usually needs no emergency help if you can cool down within 30 minutes. Get help if:
- You have a heart condition and want to start using a sauna. Ask your GP whether it’s safe for you.
- You have signs of heat exhaustion that you’re struggling to treat. Get help from NHS 111.
- You and your partner have had regular sex without contraception for over 1 year (or 6 months if your partner is 36 or over) and not got pregnant. See a GP.
- Call 999 if someone is still unwell after 30 minutes of resting somewhere cool, being cooled and drinking fluids. These are signs of heatstroke.
- Also call 999 for a very high temperature, hot skin that’s not sweating and might look red (this can be harder to see on brown or black skin), a fast heartbeat, fast breathing or shortness of breath. Confusion and poor coordination, a seizure or fit, or passing out need 999 too.