Sauna bathing has a long tradition and some intriguing research behind it. Most of that research shows an association, though, and a hot room isn’t safe for everyone.
The evidence in brief
- Large Finnish studies link frequent sauna use with lower rates of heart disease, but they’re observational and can’t prove the sauna caused the difference.
- Infrared saunas run cooler and heat the body more directly; there’s less long-term research on them than on traditional saunas.
- Keep sessions short, drink water, skip alcohol, and get out if you feel dizzy or unwell.
- Ask a doctor first if you’re pregnant, have heart disease, low or uncontrolled blood pressure, or take medicines that affect sweating or blood pressure.
Few wellness habits have as much history as the sauna. In Finland it’s ordinary household equipment, and Finnish researchers have produced some of the most cited studies on heat bathing and health. The findings are interesting. They’re also easy to oversell.
What the research shows
The best-known work comes from a long-running study of middle-aged men in eastern Finland. Published in JAMA Internal Medicine in 2015, it found that men who used a sauna four to seven times a week had lower rates of fatal heart disease and death from any cause than men who went once a week. Later analyses from the same group reported similar associations with high blood pressure and dementia.
Two things are worth keeping in mind:
- These are observational studies. People who take frequent saunas may differ in other ways, from income to fitness to social life, that also affect health. The studies adjust for some of these, but they can’t prove the sauna itself was responsible.
- The participants were mostly Finnish men using traditional saunas at high temperatures. The results may not apply in the same way to other groups, or to a 15-minute session at the gym.
Smaller trials suggest that heat exposure can temporarily lower blood pressure and improve how blood vessels respond, which fits the observational findings. Many people also simply find a sauna relaxing, and that’s a perfectly good reason to enjoy one.
Traditional versus infrared
| Traditional sauna | Infrared sauna | |
|---|---|---|
| How it heats | Heats the air, often with a stove and rocks | Infrared panels warm the body more directly |
| Typical temperature | About 160°F to 195°F | Lower, often around 120°F to 150°F |
| Feel | Hot air, with steam if water is thrown on the stones | Gentler air, slower sweat |
| Research base | Most of the long-term studies | Much less, mostly small and short studies |
Claims that infrared saunas “detox” the body or burn significant calories go well beyond the evidence.
Who should be careful
Talk to a doctor before using a sauna if you:
- are pregnant or trying to become pregnant
- have heart disease, have had a recent heart attack, or have unstable chest pain
- have low blood pressure or blood pressure that isn’t controlled
- take medicines that affect blood pressure, heart rhythm or sweating
- have a condition that makes overheating risky
Safety first
Never mix sauna use with alcohol. Alcohol increases the risk of dangerously low blood pressure, irregular heart rhythm and overheating, and it’s been linked to sauna deaths.
If you try it
- Start short: 5 to 10 minutes the first time.
- Drink water before and after.
- Sit lower if it’s too hot; heat rises.
- Get out at the first sign of dizziness, nausea or a pounding heart.
- Cool down gradually before driving or exercising.
Some people follow a sauna with a cold plunge. That combination adds its own risks, covered in our guide to cold plunges and ice baths. And if a spa pairs its sauna with “detox” claims, our guide to detox products and claims explains why sweat isn’t how your body clears toxins.
Asked and answered
How long should a sauna session be?
Many people stay 10 to 20 minutes. Start shorter, especially if you’re new to it, and leave as soon as you feel lightheaded or uncomfortable.
Do saunas detox the body?
Sweating mostly removes water and salt. Your liver and kidneys clear waste products; there’s no good evidence that sweating in a sauna removes meaningful amounts of toxins.
Can I use a sauna while pregnant?
Raising your core body temperature in early pregnancy is a concern, so talk to your obstetric provider before using a sauna or hot tub.
This guide is general information, not medical advice. Check with your doctor or pharmacist before starting a supplement, device or treatment, especially if you’re pregnant, take medicines or have a health condition.