Sauna bathing
Finnish cohort: 4-7 saunas/week associated with markedly lower cardiovascular and all-cause mortality.
Why
Sauna use combines passive heat stress with parasympathetic recovery. The Finnish KIHD cohort followed 2,315 men for ~21 years; 4-7 sessions per week was associated with a 63% reduction in sudden cardiac death and 40% reduction in all-cause mortality vs. one session per week. Effects scale with frequency and duration. Mechanisms likely include endothelial conditioning, blood-pressure reduction, and HSP-mediated repair.
Slot in your day
How to do it
How
Traditional Finnish-style dry sauna at 80-100°C for 15-20 minutes per session. 2-3+ sessions per week ideal. Hydrate well. Cool-down period after.
Ideal for
Anyone with regular sauna access; cardiovascular conditioning where exercise tolerance is limited.
Markers this may influence
Evidence
Laukkanen 2015 JAMA Intern Med (Finnish KIHD cohort, n=2,315 middle-aged men, ~21 y follow-up): 4–7 sauna sessions/week vs once/week: hazard ratio 0.37 for sudden cardiac death (95% CI 0.18–0.75) and 0.60 for all-cause mortality. Observational, but dose-response and consistent across the FINSAUNA cohort.