Sauna Benefits: What the Studies Actually Show

Short answer: Regular sauna use is linked with lower rates of fatal heart disease, high blood pressure and dementia, mainly in a large, long-running study of Finnish men. [S02] [S03] [S04] Smaller trials report benefits for some people with heart failure and mild depression. [S01] The evidence has limits: the biggest findings come from observational studies that show associations rather than cause and effect, and most trials are small. [S01] [S02] Sauna bathing is well tolerated by most healthy adults, but people with unstable angina, a recent heart attack or severe aortic stenosis should avoid it. [S06]

People use saunas for relaxation, recovery and general wellbeing. This guide sorts the sauna benefits with research behind them from the ones that are mostly marketing, and covers who should be careful.

What counts as a sauna in the research

Most studies look at one of two types:

• Traditional Finnish sauna. Short sessions of about 5 to 20 minutes at 80 to 100°C in dry air with 10% to 20% humidity, broken up by bursts of steam from water thrown on the hot rocks. [S01] This is the most studied type. [S01]
• Infrared sauna. Infrared emitters warm the body without added humidity, usually at lower temperatures of about 45 to 60°C, with similar session lengths. [S01] Infrared studies in one major review mostly used 60°C for 15 to 30 minutes. [S01]

Keep the type in mind when you read about a benefit. Most of the long-term heart and brain findings come from traditional Finnish sauna users. [S02] [S03] [S05]

Heart health: the strongest signal

The best-known sauna research comes from the Kuopio Ischemic Heart Disease Risk Factor Study in eastern Finland. [S02] Researchers followed 2,315 men aged 42 to 60 for a median of 20.7 years. [S02] Compared with men who used a sauna once a week, men who used one four to seven times a week had a 63% lower risk of sudden cardiac death after adjustment for heart disease risk factors. [S02] Similar patterns appeared for fatal coronary heart disease, fatal cardiovascular disease and death from any cause. [S02]

Session length mattered too. Men whose sessions lasted more than 19 minutes had about half the risk of sudden cardiac death of men whose sessions lasted less than 11 minutes. [S02]

These numbers are striking, but they come from an observational study. The authors concluded that sauna frequency is associated with lower risk and that further studies are needed to establish how sauna bathing and heart health are linked. [S02]

A 2018 review by the same research group in Mayo Clinic Proceedings describes the evidence as emerging. [S05] It lists several proposed ways regular sauna use might help the cardiovascular system: better function of the blood vessel lining, less arterial stiffness, changes in the nervous system's control of the heart, healthier blood lipid profiles and lower blood pressure. [S05] These are hypotheses that still need testing. [S05]

Blood pressure

In the same Finnish cohort, researchers followed 1,621 men who did not have high blood pressure at the start for a median of 24.7 years. [S04] Men who reported four to seven sauna sessions a week had a 46% lower risk of developing high blood pressure than men who reported one session a week. [S04] The result held after further adjustment for factors including alcohol use, fitness and family history. [S04] The authors suggest this may be one reason sauna use is linked with lower cardiovascular risk. [S04]

Brain health and dementia

Using the 2,315-man cohort again, researchers looked at memory diseases. [S03] Men who used a sauna four to seven times a week had a 66% lower risk of dementia and a 65% lower risk of Alzheimer's disease than men who used one once a week. [S03] The study included only men, and the authors called for more research to find out whether and how sauna bathing affects memory diseases. [S03]

Other conditions studied in small trials

A 2018 systematic review by Hussain and Cohen pulled together 40 clinical studies of regular dry sauna use with 3,855 participants in total. [S01] Only 13 were randomized controlled trials, and most had fewer than 40 participants. [S01] Most studies reported beneficial effects. [S01] Among the findings:

• Heart failure. The largest trial, of 149 patients with advanced heart failure, found small improvements in six-minute walking distance with infrared sauna therapy. [S01]
• Mild depression. One randomized trial of 28 patients found that four weeks of sauna sessions improved physical complaints. [S01]
• Rheumatic disease. An older review concluded that sauna bathing may relieve pain and improve joint mobility in people with rheumatic disease. [S06]
• Skin. The same review found that sauna bathing does not dry out the skin and may even benefit people with psoriasis, but sweating may increase itching in people with atopic dermatitis. [S06]

Hussain and Cohen concluded that regular sauna bathing has potential health benefits, but that more research is needed to find the best frequency and duration for each type of sauna and which people are most likely to benefit. [S01]

Claims with little evidence behind them

Sauna facilities often promote benefits such as detoxification, increased metabolism, weight loss, anti-aging, skin rejuvenation, better immune function and better sleep. [S01] Hussain and Cohen note that the medical evidence supporting many of these claims is not well established. [S01]

Safety: who should be careful

For most healthy adults, sauna bathing is well tolerated, according to a review in The American Journal of Medicine. [S06] That review lists three situations where sauna bathing should be avoided: [S06]

• Unstable angina
• A recent heart attack
• Severe aortic stenosis

The same review found sauna bathing safe for most people with stable coronary heart disease or an old heart attack. [S06]

Skip the alcohol. Drinking alcohol during sauna bathing increases the risk of low blood pressure, irregular heart rhythm and sudden death, and should be avoided. [S06]

Know the common side effects. In the 2018 systematic review, only eight of 40 studies reported any adverse symptoms. [S01] These included mild to moderate heat discomfort, low blood pressure or lightheadedness, airway irritation and claustrophobia, and no study reported a serious adverse event that needed emergency care. [S01] One small study of 10 men found that regular sauna use disrupted sperm production, an effect that reversed when they stopped. [S01] The reviewers said better data are needed on how often side effects happen. [S01]

Making sauna part of a wellness routine

If you enjoy saunas, the research points to a few practical takeaways:

• There is no proven ideal schedule. The Finnish findings for four to seven sessions a week are associations in men, and researchers have not established the best frequency or length for health. [S01] [S02]
• Typical sessions are short. Finnish sauna sessions in studies usually last 5 to 20 minutes. [S01]
• Watch for heat discomfort. Heat discomfort and lightheadedness are among the side effects reported in studies. [S01]
• Keep it alcohol-free. [S06]

If you are building a broader relaxation routine, our guide to breathwork for beginners covers simple breathing techniques you can use at home, and our guide to a first reiki session explains what another popular relaxation practice involves.

Frequently asked questions

How often should you use a sauna to get health benefits?

No optimal frequency has been established. In the Finnish cohort studies, men who used a sauna four to seven times a week had the lowest rates of heart disease, high blood pressure and dementia, but those studies show associations, not cause and effect.

How long should a sauna session last?

Traditional Finnish sauna sessions in studies are usually 5 to 20 minutes, and infrared sessions are often 15 to 30 minutes at lower temperatures. Researchers say more work is needed to find the best duration for each type of sauna.

Are infrared saunas as good as traditional saunas?

They have not been compared directly in enough studies to say. Infrared saunas run cooler, around 45 to 60°C, than Finnish saunas at 80 to 100°C. Most of the long-term heart and brain findings come from traditional Finnish sauna users.

Does a sauna help you detox?

That claim is not well supported. A 2018 systematic review lists detoxification among the benefits sauna facilities often promote, and notes that the medical evidence behind those claims is not well established.

Who should not use a sauna?

People with unstable angina, a recent heart attack or severe aortic stenosis should not use a sauna. Alcohol during sauna bathing raises the risk of low blood pressure, irregular heart rhythm and sudden death, so avoid it.