Posted 2/5/2019 11:24 AM (GMT 0)
I've been doing IR saunas lately, and and a similar thought had crossed my mind. Your HR increases considerably during a sauna - it's somewhat comparable to doing a decent aerobic workout. So it could be that supplements that enter the bloodstream have a better shot of making their way round the harder-to-reach areas of the body compared to a sedentary day spent on the couch.
I've not looked in to this, so at best this is literally a "shower thought" with no source, studies, etc. to back it up.