The use of heat while bathing has been an integral part of many cultures for centuries. Finland is well known as a society of avid users of the sauna, which usually produces a relatively dry heat between 70 – 100 degrees Celsius. The traditional Finnish sauna is a smoke sauna (“savusauna”) where stones are heated with a fire for several hours and then the sauna is taken after much of the smoke has cleared from the sauna building. More commonly today, saunas are heated by stoves using wood or electricity, and water is used intermittently on the stones to produce steam.
Sauna bathing usually involves several repetitions of alternating heat with cold, such as 15-20 minute heat exposures interrupted by dipping in a pond, taking a cool shower, or sitting outside. In some cultures, oak or birch twigs and leaves and/or steam are used to provide a more intense heating and massaging experience.
There are many myths regarding the physiological and psychological affects of sauna bathing. Unfortunately, we lack sufficient large, controlled studies in the medical literature to help fully understand the science supporting these myths. We have learned a significant amount about the physiologic adaptations of the body to heat bathing, however, and there is a growing body of scientific study, especially from Germany and Finland, to help understand the real benefits and risks of the practice.