Heat shock forces some cells or proteins to rejuvenate themselves. Dr Rhonda Patrick and the anti-aging guy have talked about similar ideas for hours in depth on joe rogan's podcast but I never remember the details in full.

This came from trial and error from about 6 months of trying different things in sauna. Just heating myself multiple times in hot sauna didn't work that well, but once I started to rigorously follow >1 minute cold water immersions, after 3-4x cycles I almost always ended up in a stress-less state of mental clarity (not when I felt bad/sick or didn't sleep well though). After ~4 cold immersions I also look like my skin was full of veins, connected red patches over white patches everywhere. YMMV