[r0me1]

It's all about raising your core temperature, water transfers heat to the body much more efficiently than air, so water at 104F ends up raising your body core temperature as much as a dry sauna at 170F. I did some experimentation on this, I have access to a dry sauna at my gym and I track my HR and exertion levels, I did the same with the hot tub at home making sure the water temperature doesn't go below 104F and im fully submerged to the neck, 30 mins session in both cases. The graphs look pretty much identical, same HR uptrends. So as far as cardio effects and heat shock proteins I do believe they are the same, not sure if there could be any benefit to breathing dry hot air for the lungs, but so far most benefits from sauna come from raising core temp

[pstuart]

Too lazy to find it, but Dr Rhonda Patrick (a longtime advocate for saunas for their health benefits) reported that hot tubs can provide the same results as saunas -- and they are much more pleasant to use.

[zemvpferreira]

Not to beat my own dead horse but at the heat stress needed to cause an adaptation there’s nothing pleasant about the experience. If it’s not causing nausea and palpitations, it’s not hot enough.

[weird-eye-issue]

> If it’s not causing nausea and palpitations, it’s not hot enough.

This is just so wrong. I use a 110C sauna pretty much daily, and I've done very hot onsens before, and I've never got nausea. The closest I've come is feeling lightheaded, but that's only when I combine it with ice baths. If you're feeling nauseous, you probably have a poor diet or an electrolyte imbalance

Let me guess that when it comes to exercise you think that you have to experience pain or almost pass out to get optimal adaptations? I guarantee that pushing your body to that level is highly counterproductive