> Heat shock proteins are produced by cells in response to exposure to stressful conditions (heat, cold, UV light, and during wound healing or tissue remodeling)

> Many members of this group function to stabilize new proteins to ensure correct folding or by helping to refold proteins that were damaged by the cell stress.

Source: https://en.wikipedia.org/wiki/Heat_shock_protein

I have read numerous things about the benfits of sauna, and fairly minimal downsides if healthy, and not mixed with drugs/alcohol and done in moderation.

Although I love cold weather, and grew up some years in a fairly cold area, the concern I have about varying cryo treatment is the difference between passive cryo, and active cryo therapies involving exertion. This because of the well-known relationship between cold and heart attacks stemming from exercise with cold, often seen in snow shoveling [1], [2].

[1] https://www.hallmarkchannel.com/home-and-family/how-to/cold-...

[2] https://www.clevelandheartlab.com/blog/the-heart-risk-that-c...

Why not both? Usually during the winter you have access to extremely cold showers. Where I live it is what we do - fight with snowballs outside or in the pool and then in the sauna

I feel like there is a balance here somewhere that the proponents never talk about - there is definitely a too much. Also, as with anything, the benefits are vastly overstated. Tangentially related - cold showers - when you read about them, it's some magic thing, when you do it, you just get used to it in a couple of days and it doesn't do much anything for you.

Fasting for 3 days (with water). Nothing happens. You maybe lose half a pound of fat if you walk for 4+ hours on the last day.

Etc.

Anyway, the core point is that there is a significant shock if you jump from a sauna into a cold pool. Don't try it after reading and then get a heart attack.

Do both in a series, e.g. 5x sauna interleaved with 5x cryo. That works wonders but you need to get used to it so start slowly.