After an invigorating gym workout, many of us enthusiastically look forward to removing our wet workout clothes and relaxing in a soothingly hot sauna. I know that I do. For most, the sauna after workout experience promotes both physical and mental relaxation, and contributes to an overall feeling of well-being, par excellence. The sauna has become so popular, that those who can afford to, have even installed a sauna at home. Many varieties of modern sauna are available, including low wave and far-infrared saunas. My personal favorite, however, continues to be the traditional dry heat sauna, commonly available at the neighborhood gym. Within a few minutes of use, skin temperature can rise to 100°F. resulting from sauna ambient air temperature as high as 185°F. Pulse rates usually jump significantly to aerobic exercise levels, and it has been reported that as much as a pint of body water is lost by sweating during a brief 15-20 minute medically-recommended exposure. Everyone knows that the sauna experience feels good, but just how healthy is it? I should add that I am not an expert on the subject of heat effects on human physiology, so that it was necessary for me to investigate the claims and research of others on the subject. Here’s what I uncovered:

Sauna Science

Let’s begin with a short list of common sauna health benefit claims:
Claim I (sauna and high blood pressure): Saunas may be used in a therapeutic manner for some cardiovascular problems, especially hypertension (i.e. high blood pressure). Claim II (sauna detox): Saunas are useful for detoxification; the profuse sweating eliminates toxic waste products from the body including pesticides, heavy metals, drugs, dioxins, etc.

Opponents of therapeutic sauna use (the naysayers)

What do doctors affiliated with Harvard Medical School think about saunas? One, Harvey R. Simon, M.D. editor-in-chief of Harvard Men’s Health Watch definitely has an opinion. According to Dr. Simon, “there is little evidence that they (referring to saunas) have health benefits above and beyond relaxation and a feeling of well-being”. He goes much further by warning those with poorly controlled blood pressure to “stay cool”, meaning stay out of the sauna. Nevertheless, no journal- published research is cited, and an attempt on my part to find publications attributable to Dr. Simon on the subject was unsuccessful.
Another of the nay sayers on sauna therapy is Dr. Rachel Vreeman who teaches at Indiana University School of Medicine. Dr. Vreeman is a total non-believer concerning the ability of sauna to detoxify the body. She is quoted by U.S. News and World Report Health in February 2010 as saying: “sweat contains a small amount of non-toxic dissolved minerals and trace elements including sodium, potassium,…, and copper, none of which is toxic”. She believes that we can rely wholly on our body’s natural ability to detoxify itself, and that sweating plays little or no role in this biological function. Dr. Vreeman has published extensively in the field of pediatric A.I.D.S.; but, apparently not on this topic, despite her strong skepticism regarding sauna health benefit claims.

Advocates of therapeutic sauna use (the yeasayers)

Rather than discouraging the use of dry heat sauna for those with cardiovascular problems, some researchers actually recommend using it for this purpose. In the Journal of the American College of Cardiology, 2002;v.39,no.5, researchers from Japan present evidence to support their claim that sauna may be therapeutically used for congestive heart failure patients. (Although anyone planning on using it for that purpose should be careful to follow their guidelines, in my opinion, and to start by receiving an independent medical assessment). The use of sauna therapy for heart patients is also advocated by Dr. Julian Whitaker who, along with eminent Linus Pauling, cofounded the California Orthomolecular Medical Society. However, in reviewing his website, I noticed what may be considered a hint of a conflict-of-interest on his part; namely, a link to a commercial website whereby a certain brand of infrared sauna may be purchased. Some researchers also disagree with previously stated warnings against hypertensive patients using the sauna. They, in fact, recommend its use in treating high blood pressure. For example, I discovered a study published in the German research journal Z. Kardiol 1994;83(9)-652-57 by C Siewert, et. al. which presents evidence that instead of being harmful, sauna use is actually therapeutic in treating high blood pressure. Their study, including 46 male hypertensive patients, found that both the systolic and the diastolic blood pressures, at rest and during dynamic exercise, were lowered in a statistically significant manner after they followed a three month sauna treatment.
Finally, regarding the claims that saunas are useful in detoxifying the body: I uncovered “Arsenic, cadmium, lead, mercury in sweat: a systematic review” by Margaret Sears, et. al. of Children’s Hospital of Eastern Ontario Reserch Institute and published in the the Journal of Environmental and Public Health;2012,184745. Their review work, based on 24 studies on toxicant levels in sweat, appears to support the claim that sauna-induced sweating may aid in detoxification; and, of course, completely contradicts the Indiana University researcher who claims that it does not!

How do we interpret the findings?

The heated debate (no puns intended) regarding the therapeutic value of saunas is characteristic of many in the field of medicine and health whereby researchers with seemingly similar credentials become strongly polarized around opposing viewpoints. Often they cling tenaciously to their original claims, despite the arrival of new evidence to the contrary. Why is that? Are they afraid of contradicting themselves? Or, perhaps, they’re just afraid to utter those three simple words- “I don’t know”.  Confusing, isn’t it?

Recommendations

Here’s what I personally recommend: If you have a serious health concern, you should avoid or exercise caution when using the sauna. Obviously, further research is necessary for definitive conclusions to be reached for those with major health issues. If, on the other hand, you believe yourself relatively healthy, follow the following guidelines: (1) Limit each sauna exposure to around 15-20 minutes at a time.(2) Avoid mixing alcohol or medication use and sauna use. (3) Drink lots of water both before and after each exposure. (4) Cool down after each exposure by taking a cool shower. (5) Limit the number of exposures to two or three max. (6) Importantly, listen to your body. Discontinue use if you feel dizzy or light-headed. (7) Finally, and most importantly, just lay back and enjoy the endorphin-induced feeling of euphoria that using a sauna provides. Believe me, there are far riskier activities that one can engage in other than a sauna after workout. Excessive alcohol consumption, for one. In other words, simply follow the example that the threesome pictured above are setting, and have loads of enjoyment. Thank you very much. I look forward to your input, as usual. Dr. Garrett

P.S. For a similar comparative study of wet sauna or the “steam bath”, see Spanking FIT’s “Now for Some Steaming Sauna Science”: https://www.spankingfit.com/now-wet-sauna-steam-bath-science/