How often and how long you sauna matters a lot
The protective effect of sauna bathing is dose-dependent: more sessions per week and longer total time in the sauna are linked to greater reductions in cardiovascular death. In a large Finnish study of 1,688 men and women followed for 15 years, those who took 4–7 sauna sessions per week had a 77% lower risk of fatal cardiovascular events compared with those who used it only once a week, after adjusting for other risk factors [6]. Even 2–3 sessions per week cut the risk by about 25% [6]. Another long-term study of 2,575 men over nearly 28 years found that frequent sauna users (3–7 times/week) had a 24% lower risk of cardiovascular death compared with less frequent users [3]. The message is clear: the more regularly you sauna, the stronger the protection.
Sauna combined with exercise may be especially powerful
Adding sauna bathing to a regular exercise routine appears to amplify cardiovascular improvements beyond exercise alone. In an 8-week randomized trial of 47 sedentary adults with at least one heart disease risk factor, those who did exercise followed by a 15-minute sauna session saw their systolic blood pressure drop by an extra 8 mmHg and their cardiorespiratory fitness improve more than those who exercised without sauna [2]. The sauna-plus-exercise group also had lower total cholesterol levels [2]. This suggests sauna acts as a complementary tool that enhances the heart-healthy effects of physical activity, likely through heat-induced improvements in blood vessel function and reduced inflammation.
But sauna is not a quick fix for everyone — especially those with advanced heart disease
While the observational evidence is strong for prevention, two randomized controlled trials in people with stable coronary artery disease found that 8 weeks of sauna bathing (4 times/week, 20–30 minutes) did not improve any measured marker of vascular health, including artery flexibility, blood pressure, or the ability of blood vessels to widen [1][4]. In fact, one of these trials saw a slight worsening in microvascular function in the sauna group compared with controls [1]. This suggests that once significant arterial disease is present, the benefits of sauna may be limited — possibly because the blood vessels are already too stiff or damaged to respond to heat therapy. The authors of a review note that these conflicting results may reflect a 'healthy user bias' in observational studies, where people who sauna frequently also tend to have healthier lifestyles overall [5]. So sauna is best thought of as a preventive habit, not a treatment for existing heart disease.
About These Sources
This answer is built on 6 peer-reviewed studies — published from 2019 to 2026, 1 from 2024 or later, 3 in Q1 journals, collectively cited 60 times — selected as the most relevant from 9 studies that passed quality screening, drawn from 41 papers retrieved from a database of over 500 million.
Sources used in this answer
Finnish sauna bathing and vascular health of adults with coronary artery disease: a randomized controlled trial
In a randomized controlled trial of 41 adults with stable coronary artery disease, 8 weeks of Finnish sauna (4 sessions/week) did not improve endothelial function, arterial stiffness, or blood pressure compared with controls [1].
Effects of regular sauna bathing in conjunction with exercise on cardiovascular function: a multi-arm, randomized controlled trial
In a 3-arm randomized trial of 47 sedentary adults with cardiovascular risk factors, exercise plus post-exercise sauna led to greater improvements in cardiorespiratory fitness, systolic blood pressure (8 mmHg lower), and total cholesterol than exercise alone [2].
The Interplay between Systolic Blood Pressure, Sauna Bathing, and Cardiovascular Mortality in Middle-Aged and Older Finnish Men: A Cohort Study
In a cohort of 2,575 Finnish men followed for 27.8 years, frequent sauna bathing (3–7 times/week) was associated with a 24% lower risk of cardiovascular mortality, but did not offset the risk in men with high systolic blood pressure (≥140 mmHg) [3].
Finnish Sauna Bathing and Vascular Function in Adults with Coronary Artery Disease: Preliminary Analysis of a Randomized Controlled Trial
In a preliminary randomized trial of 14 adults with coronary artery disease, 8 weeks of sauna did not improve brachial artery flow-mediated dilation or skin microvascular reactivity, and microvascular function actually decreased in the sauna group [4].
The Impact of Sauna Bathing on Cardiovascular Homeostasis: From Molecular Mechanism to Clinical Benefits
A review of observational studies and trials concluded that frequent sauna use (4–7 times/week) is associated with 63% lower sudden cardiac death and 61% lower stroke risk, but trials in advanced coronary artery disease patients show conflicting vascular benefits [6].
Sauna bathing is associated with reduced cardiovascular mortality and improves risk prediction in men and women: a prospective cohort study.
In a prospective cohort of 1,688 men and women followed for 15 years, 4–7 sauna sessions per week were associated with a 77% lower risk of cardiovascular mortality compared with once-weekly use, and adding sauna frequency improved risk prediction [7].