Why is sauna good for you?

Feet of a person sitting on a wooden platform inside a mobile sauna, with wooden walls and a wood fired stone heater on the right side, with sunlight streaming through the sauna windows.
View from inside a wooden mobile sauna with a person's feet visible at the bottom, a bucket with a ladle, and two windows showing trees and grass outside, a pleasant view.

Benefits of sauna

Benefits of cold plunge

A person relaxing in a black cold plunge tub outdoors on a sunny day, with a view of green fields, trees, and mountains in the distance under a mostly clear blue sky.