The Science of Saunas: 10 Proven Clinical Health Benefits

Updated October 2026: we added study citations for every benefit, corrected several statistics and infrared sauna claims, expanded the safety section and replaced consumer sign-up links with practitioner resources.

What is a Sauna?

Heat therapies have long been used for healing and wellness, dating all the way back to the ancient Greeks, Romans, and Mayans. The sauna is simply a small or large room designed specifically to help you sweat. What's more, a growing body of research stands behind saunas. Below are 10 clinical health benefits of saunas, with the studies behind each one, so you and your clients can see exactly how strong (or preliminary) the evidence is.

Different Types of Saunas

Today, saunas are an everyday part of many cultures, from the Finnish sauna (found in most Finnish homes, hotels and workplaces) to the Swedish bastu, the Korean jjimjilbang, and the Japanese sento bathhouse tradition. Variations of the dry and steam (or wet) saunas, as well as the latest infrared saunas, are all used for health and relaxation. Users report that a deep, healthy sweat generally relieves stress, reduces muscle tension, and delivers an overall sense of relaxation and well-being.

Over the ages, various types of dry and wet saunas have been invented, along with the latest infrared saunas that deliver radiant heat directly to the body rather than relying mainly on heating the air in the room.

Here's a look at the types of saunas to consider as you evaluate incorporating them into a health regimen:

1. Dry saunas are heated with fire, hot stones, gas, or electricity
2. Steam saunas generate steam by applying water on the heating element
3. Infrared saunas use infrared heaters to emit light that delivers radiant heat that's absorbed by the surface of the skin
4. Hybrid saunas use combinations of dry, steam, or infrared heat.

Infrared saunas are further broken down into the following types:

• Near infrared saunas
• Far infrared saunas (FIR)
• Full spectrum infrared saunas

Infrared saunas deliver direct heat via infrared light and typically run at lower air temperatures than traditional dry and wet saunas, which heat the air to raise the room temperature.

Difference between far infrared and near infrared

The main difference between far infrared and near-infrared saunas is wavelength. Near-infrared light sits just beyond the visible spectrum, while far-infrared wavelengths are much longer (roughly 3 to 100 micrometers in the definition used in a review of far infrared biology). Manufacturers make competing claims about which type penetrates deeper or is more therapeutic, but head-to-head clinical comparisons are scarce. It is also worth knowing that most of the long-term outcome data in this article come from traditional Finnish saunas, not infrared cabins.

Differences between full-spectrum saunas and infrared saunas

Full-spectrum saunas are a type of infrared sauna that combines near-, mid- and far-infrared emitters in one cabin, rather than using a single band. They often feel more intense than far infrared alone. Marketing claims that full-spectrum units "detoxify" better than other infrared saunas are not supported by clinical trials, so we would treat them with caution.

What Happens in the Body?

Whatever type of sauna therapy you choose, and regardless of the humidity level, the effects on the body are broadly similar: the skin heats up, blood vessels widen to improve circulation and blood flow, and heart rate rises. Many people also describe a "feel good" lift in mood.

Depending on the duration of sauna use, you will see circulation changes that resemble moderate exercise. In a Finnish sauna, heart rate may increase to 100 to 150 beats per minute (Hannuksela and Ellahham, 2001). In one study, a 15-minute sauna session at 72°C raised growth hormone roughly 2.5-fold in younger men, although older men showed no significant rise (Leppäluoto et al., 1987). Sauna use after training may also help endurance performance, likely through increased blood volume (see benefit 6).

Still not convinced? Then let's dive into the health benefits of sauna use, and how to accurately measure the effects.

10 Proven Clinical Health Benefits of Sauna Use

A quick note on the evidence: many of the strongest findings below come from the Kuopio Ischemic Heart Disease (KIHD) study, a long-running cohort of middle-aged men in eastern Finland. These are observational studies, so they show associations, not proof that sauna use causes the benefit. A 2018 systematic review of 40 clinical studies found mostly beneficial effects but noted that most trials were small and only 13 were randomized.

1. Support mitochondrial health. Heat appears to positively affect your mitochondria, the "batteries" powering your cells. In a 2019 trial, daily localized heat therapy (shortwave diathermy, not a sauna) preserved mitochondrial function in human leg muscle during 10 days of immobilization (Hafen et al., 2019). Whether whole-body sauna sessions produce the same effect still needs direct study.

2. Slow down Father Time (aka: aging!). In a 20-year study of about 2,300 Finnish men, 49% of those who used a sauna once a week died during follow-up, compared with 38% of those who went two to three times a week and 31% of those who went four to seven times a week. After adjusting for other risk factors, four to seven sessions per week was associated with a 63% lower risk of sudden cardiac death than one session per week (Laukkanen et al., JAMA Internal Medicine, 2015).

3. Help excrete heavy metals. Everyday exposure to potentially toxic heavy metals means even the most health-conscious people carry some body burden. A systematic review of sweat studies found that arsenic, cadmium, lead, and mercury are all excreted in sweat, sometimes at levels that match or exceed urinary excretion in people with higher exposure. The authors concluded that properly sized trials are still needed before sweating can be used as an established detoxification protocol.

4. Make your heart happy and healthy. A 2018 study of 1,688 Finnish men and women found that, after adjusting for established risk factors, physical activity and socioeconomic status, people who used a sauna four to seven times per week had a 77% lower risk of dying from cardiovascular disease than those who used a sauna once a week (Laukkanen et al., BMC Medicine, 2018).

5. Reduce blood pressure. Sauna heat helps widen blood vessels and improve circulation. Over nearly 25 years of follow-up, men who used a sauna four to seven times per week had about a 46% lower risk of developing hypertension than once-a-week users (Zaccardi et al., American Journal of Hypertension, 2017).

6. Optimize athletic performance. Heat conditioning increases plasma volume, which improves blood flow to the heart and working muscles. In a small crossover study of six distance runners, three weeks of 30-minute post-workout sauna sessions increased run time to exhaustion by 32% (equivalent to about a 1.9% improvement in an endurance time trial) and raised plasma volume by 7.1% (Scoon et al., 2007).

7. Improve muscle function and recovery. Heat exposure triggers heat shock proteins, and in the 2019 heat therapy trial above it reduced the loss of muscle size during immobilization (Hafen et al., 2019). An older study that used two one-hour sauna sessions a day at 80°C for seven days found growth hormone rose as much as 16-fold, although the response faded after the third day (Leppäluoto et al., 1986). Please note these were supervised research protocols, not recommended session lengths: typical sessions in the Finnish cohort studies averaged around 14 minutes, and the growth hormone increases are temporary.

8. Support weight management (with realistic expectations). Sauna sessions raise heart rate, but most of the weight lost during a session is sweat, which returns once clients rehydrate. There is little high-quality evidence that sauna use on its own reduces body fat, so it is best positioned as a complement to nutrition, exercise and sleep, not a fat-loss tool.

9. Boost brain health. In the Finnish KIHD cohort, men who used a sauna four to seven times per week had a 66% lower risk of dementia and a 65% lower risk of Alzheimer's disease than once-a-week users over about 20 years (Laukkanen et al., Age and Ageing, 2017). This is an association in men only, and the mechanisms are still being studied.

10. Support the immune and respiratory systems. Heat exposure increases heat shock proteins and stimulates immune signaling. In the same Finnish cohort, men who used a sauna two to three times per week had a 27% lower risk of developing respiratory diseases, and those using it four or more times per week had a 41% lower risk, compared with once-a-week users (Kunutsor et al., 2017).

11. BONUS BENEFIT: improve emotional health and mood. In a small randomized, sham-controlled trial, a single session of whole-body hyperthermia (a medical heating device, not a sauna) significantly reduced depression scores for six weeks in adults with major depressive disorder (Janssen et al., JAMA Psychiatry, 2016). Many regular sauna users report a similar lift in mood and stress levels.

Who Should Sauna, and Who Shouldn't

Sauna bathing is well tolerated by most healthy adults, but it is not for everyone. A review in the American Journal of Medicine lists unstable angina, recent myocardial infarction and severe aortic stenosis as contraindications, and warns that drinking alcohol during sauna use increases the risk of hypotension, arrhythmia and sudden death. People prone to low blood pressure or fainting should also be cautious and stay well hydrated.

For pregnancy, a 2019 systematic review found that sitting in a hot, dry sauna (70°C) for up to 20 minutes did not raise core temperature to the level linked with fetal risk, but obstetric guidance on heat exposure varies, so pregnant clients should follow their obstetric provider's advice. Regular sauna use has also been linked to a temporary, reversible drop in sperm production, which matters for clients trying to conceive. As with anything, clients should check with their medical practitioner before beginning sauna treatments.

Why Track Sauna Outcomes Client by Client

Everyone is unique and may have very different outcomes from sauna use, so it pays to track key metrics before and after use, as well as over a period of time, to understand specifically how sauna use is affecting each client.

For example, you might look at resting heart rate, heart rate variability and sleep from a wearable like the Oura Ring, home blood pressure from a connected cuff, and relevant lab panels at baseline and follow-up. Pairing that data with the sauna protocol itself (type of sauna, temperature, duration and frequency) shows which approach is actually working for each person. Many practices pair sauna with cold exposure: see our guide to the benefits of cold plunge.

How to Track Your Client's Sauna Sessions, Treatments, Outcomes, and More!

Heads Up is a clinical intelligence platform for healthcare professionals who want to track their clients' sauna sessions, treatments, and outcomes. It unifies labs, wearables, medical devices and EHR data in one longitudinal patient record, with 100+ integrations including Oura, Apple Health, Garmin, Withings, Labcorp and Quest. You can set up sauna as part of a program or protocol and track adherence, then see how it lines up with the client's HRV, sleep, blood pressure and lab results over time. Threshold alerts flag readings that need attention, and the AI copilot prepares pre-visit briefs that summarize what changed since the last appointment.

Ready to Get Started?

If you're adding sauna therapy to your longevity program, start by agreeing on goals with each client, capture baseline metrics, and then monitor how different durations and frequencies affect those same metrics. That way you can determine which type of sauna and frequency level is right for each person, with data rather than guesswork.

See how Heads Up tracks sauna protocols alongside wearable, lab and blood pressure data for your clients: request a demo.

Namaste my friends!

Dave

References

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• Laukkanen T, et al. Sauna bathing is associated with reduced cardiovascular mortality and improves risk prediction in men and women: a prospective cohort study. BMC Med. 2018;16:219. BMC Medicine
• Zaccardi F, et al. Sauna bathing and incident hypertension: a prospective cohort study. Am J Hypertens. 2017;30(11):1120-1125. PubMed
• Laukkanen T, et al. Sauna bathing is inversely associated with dementia and Alzheimer's disease in middle-aged Finnish men. Age Ageing. 2017;46(2):245-249. PubMed
• Kunutsor SK, et al. Sauna bathing reduces the risk of respiratory diseases: a long-term prospective cohort study. Eur J Epidemiol. 2017;32(12):1107-1111. PubMed
• Laukkanen JA, et al. Cardiovascular and other health benefits of sauna bathing: a review of the evidence. Mayo Clin Proc. 2018;93(8):1111-1121. PubMed
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• Hafen PS, et al. Daily heat treatment maintains mitochondrial function and attenuates atrophy in human skeletal muscle subjected to immobilization. J Appl Physiol. 2019;127(1):47-57. PubMed
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• Sears ME, et al. Arsenic, cadmium, lead, and mercury in sweat: a systematic review. J Environ Public Health. 2012:184745. PubMed
• Janssen CW, et al. Whole-body hyperthermia for the treatment of major depressive disorder: a randomized clinical trial. JAMA Psychiatry. 2016;73(8):789-795. PubMed
• Ravanelli N, et al. Heat stress and fetal risk: environmental limits for exercise and passive heat stress during pregnancy. Br J Sports Med. 2019;53(13):799-805. PubMed
• Vatansever F, Hamblin MR. Far infrared radiation (FIR): its biological effects and medical applications. Photonics Lasers Med. 2012;4:255-266. PubMed