Saunas and the Cardiovascular System: What the Research Does and Does Not Show

Regular sauna bathing is one of the more studied heat habits, and it comes up often in cardiovascular research. This page explains what that research is, what it can and cannot establish, how often people in those studies used a sauna, and who should be careful.

The short answer

A sauna session raises heart rate and widens blood vessels, placing a load on the cardiovascular system that resembles moderate walking. Long-running Finnish cohort studies have examined regular sauna bathing alongside general health measures over roughly two decades. That research is observational, meaning it shows association rather than cause. It cannot establish that sauna use produces a change in any outcome, and people who used saunas frequently differed from those who did not in ways the researchers could not fully account for. A sauna is not a treatment for any condition. Anyone with a heart condition should talk with a clinician before starting. Our research and studies page goes into how we read this literature.

What heat does during a session

When you sit in a sauna, your body works to shed heat. Blood vessels near the skin widen, blood flow shifts toward the surface, and your heart rate climbs. The Mayo Clinic Proceedings review of sauna research describes these responses as resembling those of moderate physical activity. What that means over a span of years is a separate question from what happens during a single session, and it is not settled.

What the research actually is

The most frequently cited work is the cohort led by Dr. Jari Laukkanen, summarized on PubMed, which followed a group of Finnish men over about two decades and grouped them by how often they used a sauna.

It is worth being specific about the limits. This is observational data drawn largely from Finnish men using traditional saunas, so it shows association rather than proof of cause, and lifelong habits and the surrounding lifestyle may account for part of what was observed. Effect sizes reported across this literature vary considerably between studies, which is one reason we do not quote specific figures here. Infrared saunas have considerably less direct evidence behind them, so findings should not be read across without qualification.

How often people in the research used a sauna

The cohort studies grouped participants by frequency, with sessions typically running about 15 to 20 minutes. What they measured was a habit sustained over years rather than any single long session. Treat sauna time as one part of a broader routine alongside regular movement, good sleep, and a balanced diet. Our evidence-based overview covers the wider picture.

Who should be cautious

Sauna heat raises heart rate and changes blood pressure during and after a session, so it is not right for everyone. If you have a recent heart attack, unstable angina, a serious heart rhythm problem, low or unstable blood pressure, or are pregnant, check with your doctor before starting. The same applies if you take any medication affecting heart rate or hydration. Hydrate, skip alcohol, start with shorter sessions, and step out if you feel dizzy or unwell. See our sauna safety guidelines and the guide on saunas and high blood pressure for details. This page is educational and is not medical advice, and a sauna is not a substitute for medical care.

Choosing a sauna

Most of the long-running research studied traditional Finnish saunas, though many home buyers choose infrared for lower running temperatures and easier installation. Compare options in our infrared saunas for sale and traditional saunas for sale, and use the sauna buying guide to narrow it down.

Frequently asked questions

What does the research on saunas and the heart show? Long-running observational studies have examined regular sauna use alongside general health measures over about two decades. Because that research is observational, it shows association rather than cause, and a sauna is not a treatment for any condition.

How often did people in the research use a sauna? The studies grouped participants by frequency, with sessions of roughly 15 to 20 minutes, measuring a habit sustained over years rather than any single session.

Does an infrared sauna compare to a traditional sauna here? Most of the long-running data comes from traditional Finnish saunas. Infrared saunas have considerably less direct cardiovascular research behind them, so findings should not be read across without qualification.

Who should avoid using a sauna? Anyone who is pregnant, has a cardiovascular condition, has low or unstable blood pressure, or takes medication affecting heart rate or hydration should speak with a clinician before using a sauna. See our sauna safety guidelines.