Wait what's a bedrock bath?

I just searched up on google and this us what I got:
Bedrock Bathing or Ganbanyoku is a method of body cleansing and DETOXIFICATION that involves lying down and relaxing on a heated slab of rock that is embedded in the Ganbanyoku room floor without using hot water. It is also referred to as “bedrock bathing” or “stone bathing”, but there is no bathing or water involve.