Personally I never used a sauna, a good friend of mine is using one to improve his heart function, he's also doing many other things. The best part is it worked.Is that why old men like it so much?
Sauna and the immune system
The effects of a single and a series of Finnish sauna sessions on the immune response and HSP-70 levels in trained and untrained men
The aim of the study was to investigate the effect of a Finnish sauna on the immune status parameters. The hypothesis was that hyperthermia would improve immune system’s functioning by changing the...www.tandfonline.com