桑拿與蒸氣桑拿的分別

Since you post your question in a physics forum, I suppose you want to know the difference in the physics perspective.

Steam is not necessarily the only source used in a suna for providing heat. Some suna makes use of infared radiation from "sunbeds", which contains coils or tubes heated to a temperature by eelctrical means. All these means (steam or infrared) just aims to cause sweating to the person using the sauna.

桑拿是乾的(乾蒸).
蒸氣桑拿是濕的(濕蒸).