The sauna has probably changed considerably in Finland to conform to modern living, such as apartment houses and city life. However, those who are second-generation Finnish Americans were brought up attending saunas that were close to what parents had in Finland at the turn of the century.
Actually, the Finnish sauna goes back as far as the Finns have existed. In the old days, farmers and peasants usually had a house with just one long room in which the entire family lived. They slept on pallets along the walls. Sometimes children and the elderly slept on upper portions of the Finnish masonry stoves.
The hella served as a cooking stove as well as a heating source. There was no privacy to speak of. Consequently, the sauna was extremely important when someone was ill. The sauna was heated and the sick (or dying) person had a bed arranged on the sauna bench and was made as comfortable as possible.
A woman about to give birth went to the sauna for privacy and, yes, for cleanliness. The sauna was the cleanest place on the homestead, because the mistress of the house always scrubbed it before a sauna was taken and afterwards. And when a resident died, he or she was taken to the sauna, if he wasn't already confined there during the illness. There the body was washed and prepared for burial, after which the sauna was once again carefully scrubbed.
One thing has remained a no-no. The traditional Finn will not tolerate the sauna being used as a place for sexual recreation! The belief was that the human body housed the soul, and consequently a naked body was looked on as natural with no connotations of sexuality. One's body is there to be washed and cleansed and no hanky panky. Such is the tradition.
Nowadays, there are electric saunas for apartment house dwellers, and we feel sorry for those people because they miss the lovely scent of wood smoke that goes with a traditional sauna. Oh, well, the times they are a-changing.
Many sauna devotees swear that the sauna will cure anything - upset stomachs, skin rashes, stress, gall bladders, etc. Most people suggest that a little caution be used by those who might have high blood pressure or heart disease - but certainly a mild sauna should not be harmful. As they say, folks, consult your physician (preferably a Finnish sauna goer!)