Sauna

Research summary

• A well-known Finnish cohort study (KIHD) found frequent sauna bathing (4-7 times per week) was associated with substantially lower fatal cardiovascular and all-cause mortality compared with once weekly, a finding extended by related analyses from the same cohort linking sauna use, cardiorespiratory fitness, and reduced risk of sudden cardiac death.
• A separate large cohort replicated the reduced cardiovascular mortality association and found it improved risk prediction.
• Meta-analyses of heat therapy more broadly (not sauna specifically) support modest improvements in blood pressure, vascular function, and heart failure symptoms, offering plausible mechanisms.
• The main limitation is that nearly all of the strongest mortality evidence comes from Finnish cohorts, where sauna use is a common cultural practice possibly correlated with other healthy behaviors, so causation in other populations is less certain than the consistent Finnish findings suggest.