Sauna Bathing and Long-Term Cardiovascular Health: Evidence from a Finnish Cohort Study

Cardiovascular disease remains one of the leading causes of mortality worldwide, prompting ongoing research into lifestyle factors that may reduce long-term risk. Beyond diet and physical activity, traditional practices such as sauna bathing have attracted scientific interest, particularly in Nordic countries where sauna use is deeply embedded in daily life. Long-term observational evidence from Finland suggests that regular and prolonged sauna bathing is strongly associated with reduced cardiovascular and overall mortality.

In a large prospective cohort study of 2,315 middle-aged Finnish men, participants were followed for a median period of 20.7 years. During this time, researchers documented 190 sudden cardiac deaths, 281 deaths from fatal coronary heart disease, 407 fatal cardiovascular deaths, and 929 deaths from all causes. These long-term data provided a robust foundation for examining the relationship between sauna habits and mortality outcomes. The extended follow-up period is particularly important, as it allowed researchers to assess not only short-term associations but also the cumulative effects of sauna bathing over decades.

The findings revealed a striking inverse relationship between sauna frequency and mortality risk. Men who used the sauna more often experienced significantly lower rates of sudden cardiac death compared with those who bathed only once per week. Specifically, sauna use two to three times per week was associated with a 22% lower risk of sudden cardiac death, while those using the sauna four to seven times weekly had a 63% lower risk. Similar dose-dependent reductions were observed for fatal coronary heart disease, fatal cardiovascular disease, and all-cause mortality, indicating that the benefits of sauna bathing extend beyond a single cardiovascular outcome.

In addition to frequency, the duration of sauna sessions played a crucial role. Men whose sauna sessions lasted longer than 19 minutes experienced nearly a 50% reduction in the risk of sudden cardiac death compared with those whose sessions were shorter. This suggests that both the intensity and cumulative thermal exposure may be important factors underlying the observed protective effects. Longer exposure to heat may improve vascular function, promote blood pressure regulation, and enhance autonomic nervous system balance, all of which are known to influence cardiovascular health.

Several biological mechanisms have been proposed to explain these associations. Sauna bathing induces passive heat stress, which increases heart rate and circulation in a manner similar to moderate physical exercise. This process may improve endothelial function, reduce arterial stiffness, and lower systemic inflammation. Additionally, regular sauna use has been linked to improved lipid profiles and better blood pressure control, further supporting its role as a potentially protective lifestyle practice.

In conclusion, long-term evidence from Finnish men indicates that frequent and longer sauna bathing is consistently associated with substantially lower risks of cardiovascular and all-cause mortality. While these findings are observational and cannot prove causation, the strength and consistency of the associations suggest that sauna bathing may be a valuable component of a heart-healthy lifestyle. These results, reported in JAMA Internal Medicine, highlight the potential public health relevance of traditional practices when supported by rigorous scientific research (JAMA Internal Medicine, 2015).