Regular sauna use supports heart health and longevity

Regular sauna use is linked to better cardiovascular health and lower mortality, and in the long-running Finnish study behind most of this evidence the link is strong, consistent and dose-dependent. It is also observational. The studies show that frequent sauna users live longer, but they cannot establish that the sauna is the reason, because healthier people may simply use saunas more often. No randomized trial has tested sauna use against hard outcomes like death.

Short randomized trials, lasting weeks rather than years, have tested what repeated heat sessions do to heart-health markers. Two 2025 reviews pooling them found blood pressure a few points lower after repeated sessions, roughly 2 to 5 mmHg systolic depending on the group and type of heating, and no reliable change in artery stiffness, how well arteries widen, cholesterol, blood sugar or inflammation. Most of those trials used hot water bathing or a lower-temperature infrared sauna rather than a traditional Finnish sauna.

The core observational evidence comes from the Kuopio study in eastern Finland, which tracked how often people used saunas against how long they lived. Compared with using a sauna once a week, using it 4 to 7 times a week was associated with roughly a 50% lower risk of dying from cardiovascular disease, a 63% lower risk of sudden cardiac death, and about a 40% lower risk of death from any cause. Using it 2 to 3 times a week showed smaller reductions. Sessions of about 19 minutes or longer at around 174F showed stronger associations than shorter or cooler ones. A later analysis extended the findings to women as well as men. About ten analyses of this one population, all from one research group, make up the long-term evidence; no study elsewhere has reported on regular sauna use and deaths from heart disease in the general population.

During a session, heart rate and core temperature rise to levels similar to moderate exercise, and blood pressure falls for a while afterward; a single session also briefly improves how well arteries widen. Whether repeated sessions build lasting changes is less clear. Beyond a modest drop in blood pressure, the trials have not shown the longer-term changes in the arteries and the increase in heat shock proteins that reviews of the mechanism propose.

So the picture is a strong, consistent association in one population, a modest measured effect on blood pressure in short trials, and no trial of long-term outcomes. Whether it is the sauna itself doing the work is not settled. Almost all of the long-term evidence concerns traditional dry Finnish saunas; infrared saunas, steam rooms and heat wraps are studied far less. The trials in people with heart failure used 15-minute infrared sessions at 60C (140F), cooler than a Finnish sauna, in study settings. One study in Japan followed 129 people admitted to hospital with severe heart failure for five years: 64 had these sessions daily in hospital and then at least twice a week at an outpatient clinic, and 65 patients matched for age, sex and severity had usual care only. Readmission for heart failure or death from heart disease occurred in 31% of the sauna group and 69% of the usual-care group, and 8 and 12 people died. Patients were not randomly assigned, the study looked back at patients already treated, and the sauna group came to the hospital twice a week while the usual-care group came monthly, which the authors say may have affected the result. It was run by the group that developed this form of sauna therapy, and no randomized trial has tested these outcomes.

On safety, a 2001 review in The American Journal of Medicine describes sauna bathing as well tolerated by most healthy adults and children. It names unstable angina, a recent heart attack and severe aortic stenosis as reasons not to use a sauna, while describing sauna use as safe for most people with stable coronary heart disease or an older heart attack. It reports that very few heart attacks and sudden deaths occur in saunas, and that drinking alcohol during sauna use increases the risk of low blood pressure, abnormal heart rhythm and sudden death. A 2018 systematic review of 40 studies found one reporting a harm, a study of 10 men in which sperm production was disrupted and recovered after sauna use stopped, and states that more and better data on side effects are needed. For people with heart disease, including heart failure, how these findings apply to their own condition is a conversation with their clinician.