Sauna therapy has been used for hundreds of years in the Scandinavian region as a standard health activity. Studies document the effectiveness of sauna therapy for persons with hypertension, congestive heart failure, and for post-myocardial infarction care. Some individuals with chronic obstructive pulmonary disease (COPD), chronic fatigue, chronic pain, or addictions also find benefit. Existing evidence supports the use of saunas as a component of depuration (purification or cleansing) protocols for environmentally-induced illness. While far-infrared saunas have been used in many cardiovascular studies, all studies applying sauna for depuration have utilized saunas with radiant heating units. Overall, regular sauna therapy (either radiant heat or far-infrared units) appears to be safe and offers multiple health benefits to regular users. One potential area of concern is sauna use in early pregnancy because of evidence suggesting that hyperthermia might be teratogenic. (Altern Med Rev 2011;16(3):215-225)
Key words: sauna, thermal chamber, thermal stress, hyperthermia, infrared, far-infrared, congestive heart failure, CHF, myocardial infarction, MI, chronic heart failure, hypertension, weight loss, anorexia nervosa, depression, autoimmunity, fatigue, multiple chemical sensitivities, MCS, pesticides, polychlorinated biphenyls, PCBs, solvents, sweating, pregnancy, congenital defects, deputation, cleansing, detox, detoxification, purification
Saunas have been utilized for hundreds or years, especially in the Scandinavian countries. Finland, with a population of five million, has close to one million saunas. Most Finns take a sauna bath weekly and grew up hearing the adage: "If the sauna, schnapps, and birch tar don't help, then death is near." (1)
There are several distinct types of saunas: Finnish steam sauna (Finnish steam bath), dry-heat sauna, infrared saunas, and far-infrared (FIR) saunas.
Radiant-heat Saunas (Finnish Steam Saunas and Dry-heat Saunas)
When the term "sauna" is used in the medical literature without any modifiers (e.g., infrared), it generally refers to the Finnish steam sauna. This sauna uses a wood-paneled room with wooden benches and a radiant heater that keeps the temperature between 70 and 100[degrees]C (158-212[degrees]F) with a face level temperature of 80-90[degrees]C (176-194[degrees]F). Steam is produced by pouring water over heated rocks. Generally enough steam is produced to create a humidity of 50-60 g [H.sub.2]O vapor/[M.sup.3]. Standard length of a Finnish sauna is 5-20 minutes in the sauna, followed by cold immersion (swim or shower) and a period of room temperature recovery before repeating. In a single sauna session, this pattern is repeated 2-3 times.
Dry-heat saunas are essentially the same as Finnish steam saunas; however, the room used is dry so steam is not produced. The procedure for these saunas is also roughly the same as that described for Finnish steam saunas.
Infrared Saunas (Infrared and Far-infrared Saunas)
Infrared saunas utilize a different heating element and typically do not achieve the same temperatures as the radiant heat saunas. There are also no hot rocks on which to splash water for humidity. There are two main types of infrared saunas--infrared and far-infrared (FIR).
Infrared saunas use incandescent infrared heat lamps to produce heat. They emit primarily near-infrared wavelengths, with lesser amounts of middle-infrared, and perhaps a small amount...