Sauna benefits: what research has found, and where it stops

Sauna benefits: what research has studied

This is an evidence page. If you are planning a home sauna, the equipment questions are covered elsewhere. Here we describe what published studies looked at, what they found and how much weight each finding can carry. Euphorium does not diagnose, treat or prevent medical conditions and does not promise any health, recovery or performance result.

Long-term Finnish cohort studies

The most cited findings come from the Kuopio study in eastern Finland. Laukkanen and colleagues followed 2,315 middle-aged men for about 20 years and grouped them by how often they used a sauna: once, two to three times, or four to seven times a week. Men who used a sauna more often had lower rates of fatal cardiovascular events and death from any cause. Later analyses of the same cohort, including one by Kunutsor and colleagues, reported lower rates of respiratory disease among frequent users.

These are associations, not proof of cause. People who use a sauna often may differ in many ways from those who do not, such as income, activity, social life and general health. The participants were Finnish men, so the results may not apply equally to women, younger people or other populations. A 2018 review by the same research group summarises these findings and their limits.

Short-term effects on the body

During a session, heart rate rises, blood vessels in the skin widen and you sweat. Ketelhut and Ketelhut found that blood pressure and heart rate responses in the sauna resembled those during moderate exercise. That is a useful way to think about a session: a real, short-term load on the heart and circulation, which is why safety matters.

Clinical trials

Hussain and Cohen systematically reviewed 40 clinical studies of regular dry sauna bathing involving 3,855 participants. Only 13 were randomised controlled trials, and most were small. Many reported positive effects, but the authors concluded that higher-quality research is needed on frequency, duration and side effects. One small study reported reversible disruption of sperm production in men who used a sauna regularly.

Colds and skin

A trial by Ernst and colleagues compared 25 regular sauna users with 25 controls over six months. The sauna group had fewer colds, mostly in the final three months, but colds lasted just as long and were just as severe. The authors said further studies were needed. A small German study by Kowatzki and colleagues found that regular sauna users showed more stable skin barrier measures after a session than non-users. Neither study is large enough to support a promise.

Recovery and relaxation

The sauna recovery benefits people describe are mostly about feeling relaxed and loosened up after exercise, and research on recovery from heat is much thinner than for cold water. When people list the benefits to sauna use, relaxation and routine tend to come first; those are personal experiences rather than measured outcomes.

Different heat sources have different evidence bases. Read our separate guides to infrared sauna benefits and steam room benefits for what has been studied in those rooms.

What is uncertain or overstated

Many popular claims about the health benefits of using a sauna go well beyond the studies above. Honest sauna benefits are modest; these are the most common overstatements.

Weight loss

You will often weigh less after a session, but almost all of that is water lost in sweat, and it returns when you drink. Sauna weight loss in the sense of losing fat is not supported by the research we cite. Your heart works harder in the heat, so you use some extra energy, but a sauna is not a substitute for exercise or diet.

Detox

Sweat is mostly water and salts. The idea that sweating in a sauna flushes out toxins in meaningful amounts is not supported by the reviews we cite, and we do not describe a sauna as a detox.

Immunity and illness

One small trial found fewer colds among regular users, and cohort studies report associations with respiratory health. None of this shows that a sauna treats an infection. If you have flu or a fever, or feel unwell, skip the sauna: those are reasons to rest, not to add heat stress.

Skin and the 'sauna face' glow

The flushed look people call sauna face is increased blood flow to the skin, and it fades within a short time after you cool down. One small study measured skin barrier changes in regular users, but that does not support claims about anti-ageing, acne or skin conditions.

Sleep

Many people say an evening session helps them wind down. Good-quality trials on sauna and sleep are scarce, so treat it as a personal observation. If it helps you relax, that is a reasonable reason to use one.

Session length, frequency and the benefits of sauna every day

No study has proven an ideal dose. The Finnish cohort recorded both how often and how long men used a sauna, and the German skin study used two sessions of 15 minutes at 80°C in regular users. Those were the conditions of each study, not instructions.

In practice, people tend to settle on a pattern like this:

• Start with shorter, cooler sessions and leave as soon as you feel uncomfortable.
• Cool down between rounds with a shower and a rest.
• Drink water before and after.
• Build up gradually over weeks rather than in a single session.

Whether the benefits of sauna every day are greater than a few times a week is not something the research can answer for an individual. The cohort studies saw associations with more frequent use, but they cannot separate the sauna from everything else about the people who used it. Use a frequency that fits your routine and leaves you feeling well.

If you are deciding between heat types, our comparison of sauna vs steam room explains how dry and humid heat differ. Many people pair heat with cold; our guide to a sauna and cold plunge routine covers how they structure that safely.

The benefits of a sauna room at home are partly practical: no travel, no booking and the freedom to keep sessions short and frequent. Those sauna bath benefits are about access, and they matter more than any single study when it comes to whether you actually use it.

Who should ask a doctor first

Sauna use is well tolerated by most healthy adults, according to reviews by Hannuksela and Ellahham and by Kukkonen-Harjula and Kauppinen. Those same reviews list situations where it is not appropriate or needs medical advice. Ask a qualified healthcare professional before using a sauna if you:

• have heart disease, especially unstable angina, a recent heart attack or severe aortic stenosis;
• have very high or very low blood pressure, or take medication that affects it;
• are pregnant or trying to conceive;
• have a condition affecting temperature regulation, sweating or circulation;
• are unwell, have a fever or are recovering from illness.

Alcohol is a major avoidable risk. Drinking before or during a sauna raises the risk of low blood pressure, irregular heart rhythm and sudden death, so never combine the two. Children should only use a sauna with an adult and at lower heat.

Read the full safety and medical disclaimer.