By Matt Justice. Reviewed against published research. Last updated: October 2026. This page is educational and is not medical advice.
Short answer: regular sauna use has real research behind it, strongest for heart and circulation, with smaller studies on pain, fatigue and quality of life. Much of the best data comes from traditional Finnish saunas, and so far research cannot say whether infrared is better or worse for these benefits. The main risks are dehydration, overheating and dizziness, and some people, including anyone pregnant, trying to conceive or managing a heart condition, should talk to a doctor first. Claims about fat loss, curing disease or replacing exercise do not hold up.
How strong is the evidence?
Stronger than skeptics assume, weaker than marketing claims. A 2018 systematic review of regular dry sauna use found 40 clinical studies with 3,855 participants, covering both Finnish and infrared saunas. Most reported benefits, but only 13 were randomized controlled trials and most were small, under 40 people. The authors concluded that sauna bathing has potential health benefits, that more high-quality data is needed, and that there was not yet enough evidence to say infrared and Finnish saunas differ in their effects.
So when you see a sauna company list twenty benefits, remember that association is not causation, and many of those claims come from small studies or none at all.
Benefits with the best research behind them
| Benefit | What the research shows | Sauna type studied |
|---|---|---|
| Heart health and longevity | A Finnish study of 2,315 men followed for about 21 years linked 4 to 7 sessions a week with 50% lower risk of fatal cardiovascular disease and 40% lower all-cause mortality, compared with once a week. Observational, so it shows association, not proof. | Traditional Finnish |
| Heart failure (supervised) | A multicentre randomized trial of 149 heart failure patients reported better walking distance and heart function after 2 weeks of “Waon therapy.” Most of this research comes from one Japanese group, mostly with hospitalized patients. | Far infrared |
| Circulation and blood pressure | Several smaller studies report improved vascular function and blood pressure with regular sessions. | Both |
| Pain and fatigue | Small studies suggest benefits for fibromyalgia, rheumatoid arthritis, ankylosing spondylitis, chronic fatigue and chronic pain. | Mostly infrared |
| Exercise and quality of life | Studies report better exercise performance in athletes and improved quality of life measures. | Both |
The pattern across these studies is that heat stress, from either sauna type, makes you sweat and raises your heart rate in a way that appears to drive useful adaptations. That is why consistent use matters more than any single session.
Claims that do not hold up
- Fat loss. The weight you lose in a session is mostly water and comes back when you rehydrate.
- Replacing exercise. Sauna may complement exercise, but it is not a substitute for it.
- Curing disease. No sauna cures cancer, autoimmune disease or anything else, and anyone claiming otherwise is selling something.
- Testosterone boosts. The evidence does not support the marketing.
- “Full spectrum” as a cure-all. More wavelengths on a spec sheet do not mean more benefit. See my heater types guide.
Risks and who should be careful
Dehydration and overheating
You can lose a lot of fluid in a session. Signs of trouble include dizziness, headache, nausea, confusion or feeling faint. Get out, cool down and rehydrate if you notice any of them. Do not sauna after drinking alcohol.
Low blood pressure and dizziness
Heat lowers blood pressure, and standing up quickly afterward can make you light-headed. Stand up slowly and sit for a minute before walking out.
Male fertility
The only adverse outcome in the systematic review was from a small study of 10 men using a Finnish sauna for 3 months, which found reduced sperm count and motility. The effect reversed after they stopped. If you are trying to conceive, it is reasonable to cut back.
Pregnancy, heart conditions and medications
If you are pregnant, have a heart condition, have low blood pressure, or take medications that affect blood pressure, heart rate or sweating, talk to your doctor before using any sauna. The heart failure research above involved supervised, medically managed sessions, which is not the same as a home sauna.
EMF exposure
This is the risk I test for most, because the sauna you sit in every day should be what it claims to be. Many “low EMF” saunas only address magnetic fields and ignore electric fields and body voltage, which I measure in the seated position. See how I test saunas for EMF and my sauna blanket test results for an example.
Why I take sauna benefits seriously
I started using infrared saunas on a functional medicine doctor’s advice, and they have been part of my routine through some hard health seasons since. I share that story here, but I also want you to have the research, not just my experience.
How to use an infrared sauna safely
- Hydrate before and after, and replace electrolytes if you sweat heavily.
- Start with shorter sessions at a moderate temperature and build up. Most infrared studies used about 140°F (60°C) for 15 to 30 minutes.
- Leave if you feel dizzy, nauseous or unwell.
- Cool down gradually and stand up slowly afterward.
- Skip it after alcohol, and check with your doctor first if any of the conditions above apply to you.
Frequently asked questions
Are infrared saunas safe?
For most healthy adults who stay hydrated and keep sessions reasonable, yes. The 2018 systematic review found no serious adverse events across 40 studies. Pregnant people, anyone trying to conceive, and people with heart conditions or on certain medications should check with a doctor first.
Is infrared or traditional sauna better for health benefits?
Research cannot say yet. Most long-term longevity data comes from traditional Finnish saunas, while much of the heart failure research used far infrared. Both raise your core temperature and make you sweat, which appears to drive the benefits.
Do infrared saunas help you lose weight?
Not in a meaningful way. The weight lost during a session is mostly water and returns when you rehydrate.
How often should you use an infrared sauna?
The Finnish longevity data saw the strongest associations at 4 to 7 sessions a week, but that was traditional sauna in an observational study. Consistency matters more than any single session; start slowly and build up.
Sources
- Hussain J, Cohen M. Clinical Effects of Regular Dry Sauna Bathing: A Systematic Review. Evidence-Based Complementary and Alternative Medicine, 2018.
- Laukkanen T, et al. Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events. JAMA Internal Medicine, 2015.
- Garolla A, et al. Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Human Reproduction, 2013.
This page is for education only and is not medical advice. Talk to a qualified healthcare provider about your own situation.
