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...