Unfortunately, yes, just about everything beyond the basics in longevity stuff has that as a possible confounder. Sauna is a fairly passive thing, though, I would expect less of an effect.
Itβs not only that confounder but also the fact that the studies show massive risk reductions that are really surprising. Considering how much finns apparently go to the sauna compared to similar countries and how good the sauna appears to be based on the studies, itβs weird that they have similar health stats at a country level.
Yeah, I didn't realize how little overall effect it had. Pretty much either has to be a confounder or like exercise: much more benefit in terms of quality than quantity.
One big problem with longevity is so many things go wrong--completely removing even a major cause of death produces surprisingly small gains.
