Dr. Rhonda Patrick on the Joe Rogan Experience #672, fact-checked

What the evidence shows: The figure comes from an observational Finnish cohort, not a trial showing that sauna use caused a mortality decrease. In a study of 2,315 middle-aged men followed for a median of 20.7 years, those reporting four to seven sauna sessions per week had an adjusted all-cause mortality hazard ratio of 0.60 compared with men reporting one weekly session. That is an association consistent with about 40% lower relative hazard, but participants were not randomly assigned and the authors called for further studies to establish a mechanism. The number is close to the study result, while the wording turns an association into a proven causal effect.