Finnish Sauna Bathing in Cardiovascular Health: Mechanistic Insights, Mortality Benefits, and Safety Considerations for At-Risk Populations

Finnish sauna bathing, a traditional practice involving dry heat exposure, is associated with significant cardiovascular benefits, especially in lowering the risk of hypertension and reducing cardiovascular disease mortality.Longitudinal cohort studies demonstrate that frequent sauna use (4-7 sessions/week) lowers incident hypertension risk by 47% (HR: 0.54, 95% CI: 0.32-0.91)and reduces sudden cardiac death risk by 63% (HR: 0.37, 95% CI: 0.18-0.75)via mechanisms including enhanced endothelial nitric oxide bioavailability, peripheral vasodilation, and improved autonomic regulation.Synergistic interactions with cardiorespiratory fitness further enhance the benefits, with high fitness levels combined with frequent sauna use being associated with 69% lower cardiovascular disease (CVD) mortality.Mechanistically, acute sauna exposure induces plasma volume redistribution (70% cutaneous blood flow increase) and chronic adaptations such as heat shock protein upregulation, reducing oxidative stress and arterial stiffness.Despite these benefits, sauna bathing poses risks for specific cardiovascular populations: unstable angina, recent myocardial infarction (<3-6 months), and severe aortic stenosis are absolute contraindications due to hemodynamic instability, while decompensated heart failure and orthostatic hypotension necessitate caution.Clinical trials highlight transient myocardial ischemia in 93% of stable coronary artery disease patients during sauna use, underscoring the need for individualized protocols.This review synthesizes evidence supporting sauna therapy as a non-pharmacological adjunct for cardiovascular health while emphasizing safety considerations in high-risk cohorts.