When it comes to your health, sometimes the simplest strategies can have a tremendous impact. Sweating in a sauna is one simple change with many health benefits, including the ability to reduce cardiovascular risk and improve mitochondrial function. It also correlates well with a reduction in the risk for dementia.
A Finnish proverb says, "The sauna is Finland's medication … and a poor [person's] apothecary."1 Saunas have been used for nearly 2,000 years in Finland for stress relief and to improve health. Not surprisingly, much of the research on the health benefits of saunas comes from Finland, a country where saunas are nearly as common as television sets.2 They're often found in private homes, offices and factories, and are an integral part of Finnish life.
In addition to offering cardiovascular and neurological benefits, they are being used by athletes for post-workout muscle relaxation and as a means of improving athletic performance. Another important aspect to sauna use has been detoxification. While there has been more than adequate research demonstrating the ability of sweating in a sauna to detoxify the body of heavy metals and other toxins, one letter published in the Journal Environmental International has renewed the debate over its effectiveness.3
Experts Call Detox Sweating a Myth
Some experts teach that your liver and kidneys are the only way your body has of removing toxins.4 In essence, they believe using a sauna to detoxify from environmental toxins and heavy metals is nothing more than a myth. In making the argument, some have indicated there is usually a grain of truth to the heart of every myth, believing toxic sweat is no exception.
The authors of the correspondence5 published in the journal Environmental International suggest the amount of toxins the body is capable of releasing through sweat is minuscule, and that the amount of pollutants — such as persistent organic compounds such as pesticides, flame retardants and now-banned polychlorinated biphenyls (PCBs) — in the human body is so low they're essentially meaningless.
Yet these toxins and known carcinogens are banned from use because they trigger disease. According to the lead author, a typical person doing 45 minutes of high-intensity exercise could sweat a total of 2 liters each day, including normal everyday perspiration. This sweat would contain less than one-tenth of a nanogram of the pollutants discussed.
Hence, he believes there is no way to sweat enough to get rid of even 1 percent of the chemicals you ingest in your food in a single day.6 Ironically, and perhaps tellingly, this statement completely contradicts the claim that the toxic burden is essentially meaningless to begin with.
Another writer wrote an infrared sauna was nice and left her feeling euphoric after sitting in 30 minutes, but she believed the feeling was similar to an endorphin rush after working out,7 and that aside from the feelings of euphoria there was no science to back up the idea the sauna aided in detoxification. While these articles are circulated and read, they do not reflect the body of scientific and research evidence demonstrating the effectiveness of saunas to assist the body in eliminating environmental toxins and heavy metals.
Sweating Does Release Toxins From Your Body
Mixed with your sweat is a substance called urea, for which urine is named. In a paper published8 in the Journal of Biological Chemistry, researchers estimated up to 1.12 milligrams (mg) of urea is dissolved in every cubic centimeter of sweat. While this sounds like a small amount, the average person sweats up to 700 cubic centimeters of liquid each day, which means urea excreted in your sweat is responsible for up to 7 percent of your daily elimination of urea.9
Research has also determined that metals are excreted in measurable amounts, and many researchers consider sweating a safe and effective way to eliminate arsenic, cadmium, lead and mercury.10 This meta-analysis considered 24 published studies in which sweat collection and concentration were analyzed. They found individuals with a higher burden of toxins would generally sweat amounts exceeding plasma or urine concentrations.
These studies determined dermal excretion through sweating could match or surpass urinary excretion. Notably, cadmium was more concentrated in sweat than in blood plasma and mercury levels could be normalized with repeated sauna use.11 Another study evaluated the blood, urine and sweat from 20 individuals and analyzed them for approximately 120 compounds, which were found in varying amounts in each of the different fluids. According to the authors:12
"Many toxic elements appear to be preferentially excreted through sweat. Presumably stored in tissues, some toxic elements readily identified in the perspiration of some participants were not found in their serum. Induced sweating appears to be a potential method for elimination of many toxic elements from the human body."
Bisphenol-A (BPA) is a ubiquitous chemical contaminant associated with a number of adverse human health conditions. In a study designed to assess the relative concentration of BPA in blood, urine and sweat, researchers found BPA could be identified in the sweat or 80 percent of the participants, even in some who had no BPA detected in serum, blood or urine.13
They concluded biomonitoring using blood or urine may underestimate the total burden, and sweat analysis should be considered as it appeared to be useful for elimination of BPA.
Chemicals in the phthalate family are found in everyday consumer products, resulting in high exposure for some individuals and groups. Multiple studies have demonstrated statistically significant relationships between exposure to phthalates and disease. In one study,14researchers evaluated the effectiveness of excretion of phthalates and metabolites through sweat.
They found some phthalates were measurable in sweat but not serum suggesting retention and bioaccumulation. They concluded induced perspiration could be useful to facilitate elimination of toxic phthalate compounds, and that sweat analysis may help establish the existence of the bioaccumulation of 2-ethylhexl phthalate.15