I wonder if there are similar cardiovascular benefits for hot tubs. Could it be that it's breathing the hot air in the sauna that's beneficial rather than a general increase in body temperature?
I'm asking because we are thinking about installing a hot tub at some point.
Martin Pall hypothesizes that sauna therapy increases the availability of tetrahydrobiopterin (BH4) through multiple mechanisms [1]. A small study with people with chronic fatigue syndrome provides evidence to confirm this [2] (I don't think this publication is peer reviewed). I believe there is an association between BH4 and cardiovascular health, but this is not my field.
Martin Pall has a history of dubious hypotheses. It seems more likely that it is simply the increase in heart rate that improves cardiovascular health.
I'm asking because we are thinking about installing a hot tub at some point.