Association between sauna bathing and fatal cardiovascular and all-cause mortality events.
Level 3 - non-randomized controlled study
Prospective cohort study
PubMed 25705824 · doi:10.1001/jamainternmed.2014.8187
What was done
Prospective cohort study of 2,315 middle-aged men (aged 42–60 years) from Eastern Finland in the Kuopio Ischemic Heart Disease Risk Factor Study, enrolled between 1984 and 1989. Frequency (1, 2–3, or 4–7 sessions/week) and duration (<11, 11–19, or >19 minutes/session) of sauna bathing were assessed at baseline and followed for a median of 20.7 years for outcomes including sudden cardiac death (SCD), fatal coronary heart disease (CHD), fatal cardiovascular disease (CVD), and all-cause mortality.
What was found
During follow-up, 190 SCDs, 281 fatal CHDs, 407 fatal CVDs, and 929 all-cause deaths occurred. After adjusting for CVD risk factors, compared with 1 session/week, having 4–7 sessions/week was associated with an adjusted hazard ratio (HR) of 0.37 (95% CI, 0.18–0.75) for SCD (P for trend = .005), with similar inverse associations for fatal CHD, fatal CVD, and all-cause mortality (all P for trend ≤ .005). Compared with sessions <11 minutes, sessions >19 minutes had an adjusted HR of 0.48 (95% CI, 0.31–0.75) for SCD (P for trend = .002), with significant inverse trends also seen for fatal CHD and CVD (P ≤ .03), but not for all-cause mortality.
Why it matters
This study provides strong prospective cohort evidence linking frequent and longer sauna bathing to substantial dose-dependent reductions in fatal cardiovascular events and overall mortality.
Limits
The study is observational, leaving open the possibility of residual confounding or healthy-user bias. Sauna exposure was assessed only at baseline, and the cohort included only middle-aged Finnish men, limiting generalizability to women, other age groups, and non-Finnish populations.
Cited by
- supports Studies on Finnish men show that regular sauna bathing is associated with lower long-term mortality and reduced cardiovascular disease deaths.