This is an exclusive excerpt from my book, The Physiology of Yoga.
Our bodies are regularly and inevitably exposed to toxins – poisonous substances produced by living organisms, including those produced in the body itself, such as lactic acid and microbial waste products in the gut. Your body removes these toxins through the liver, feces, and urine. The liver, specifically, alters toxic substances chemically, yielding them harmless and ready for excretion.
The physiological processes through which the body identifies, neutralizes, and eliminates toxic substances and metabolic byproducts is called detoxification. Our bodies naturally possess the capacity to perform these processes very effectively. Without an effective detoxification system, we would be very unwell.
Sweat glands are often perceived to play an important excretory function, similar to that of the kidneys. However, in a comprehensive review, Baker (2019) concluded that the role of the sweat glands in eliminating waste products and toxicants from the body seems to be minor compared with other avenues of breakdown (liver) and excretion (kidneys and gastrointestinal tract). Studies suggesting a larger role of sweat glands in clearing waste products or toxicants from the body (e.g., concentrations in sweat greater than that of blood) may be an artifact of methodological issues rather than evidence for selective transport. Nevertheless, studies have shown that perspiration plays a role in skin hydration and microbial defense (Schröder and Harder 2006; Watabe et al. 2013). So, it appears that heavy sweating in a hot yoga class or in a sauna might not help us to relinquish all those perceived toxins after all.
Does heavy sweating during hot yoga detox the body?
Even with our bodies’ integrated detoxification system, there are still some chemicals that cannot be easily removed through these processes, including persistent organic pollutants (found in pesticides), phthalates (found in hundreds of plastic products), bisphenol A (found in many food containers and hygiene products), and heavy metals (found in agriculture, medicine, and industry). Known to accumulate in the body and take a very long time, potentially years, to be removed, these chemicals may be linked to various chronic diseases including asthma, cancer, autism, and attention-deficit/hyperactivity disorder (Sears & Genuis, 2012).
The idea that a certain yoga pose, a certain diet, or a certain product can remove these stubborn toxins from the body is a tempting one. However, there is little to no evidence that one pose, diet, or product can do just that. In a 2015 review of all studies to date examining the efficacy of detox diets, Klein and Kiat found that we have very little clinical evidence to support the use of detox diets despite a booming detox industry and product packaging that makes bold but unsubstantiated claims. Although a small number of studies have found commercial detox diets might enhance liver detoxification and eliminate persistent organic pollutants, these studies had flawed methodologies and small sample sizes, thus reducing their scientific credibility. Klein and Kiat concluded:
To the best of our knowledge, no randomised controlled trials have been conducted to assess the effectiveness of commercial detox diets in humans. This is an area that deserves attention so that consumers can be informed of the potential benefits and risks of detox programs.
Does heavy sweating during hot yoga detox the body?
As for yoga, there has been no research, as far as we are aware, to show that it improves the body’s natural detoxification system. This might be because our body already does a fantastic job of detoxification on its own. If you were not able to remove toxins from your body, you would know, as a plethora of symptoms would occur, even fatal ones.
This is not to say that yoga (or exercise in general) has no effect on our body’s ability to detoxify, but the benefits likely come from exercise’s ability to decrease inflammation and increase vascularization or blood supply. While some inflammation is necessary in recovering from a wound or infection, chronic inflammation is hard on the body and weakens many systems. Long-term inflammation underlies many serious diseases, including cardiovascular disease and diabetes, while cancer, obesity, osteoporosis, Alzheimer’s disease, and cardiovascular disease have all been linked to increased biomarkers of inflammation (Tabas and Glass, 2013).
It is well established that exercise creates an anti-inflammatory response in the body – one of its most potent benefits (Flynn, McFarlin, and Markofski, 2007). When inflammation is reduced, all systems of the body can work more efficiently, including those of digestion and detoxification. Another well-known benefit of exercise is increased circulation, so more blood, which contains essential nutrients and oxygen, is available for digestion and detoxification. In these ways among other benefits, exercise can certainly help optimize our body’s detoxing processes.
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So, do twists detoxify your body? Neither yoga nor diet do anything that our bodies cannot do on their own. However, yoga can optimize the body’s natural detoxification system, not through one specific pose such as a twist, but through the powerful benefits of decreasing inflammation and increasing circulation that come with exercise. Trust that your body is fully equipped to handle toxins and other unwanted substances.
Another thing we can do to improve our detoxification process is to simply reduce our exposure to toxins. While detox diets do not work in the way they are often advertised to, nearly all diets encourage healthful, balanced eating, which reduces your exposure to harmful products, including artificial ingredients found in junk food. We can also reduce our exposure to persistent organic pollutants by eating organically grown food. We can reduce the burden on our liver by drinking only moderate amounts of alcohol. Finally, keeping active with moderate exercise, yoga or otherwise, will help the body do what it does very well.
References:
Baker, L. 2019. “Physiology of Sweat Gland Function: The Roles of Sweating and Sweat Composition in Human Health.” Temperature (Austin) 6 (3): 211‐259.
Flynn, M.G., B.K. McFarlin, and M.M. Markofski. 2007. “The Anti-Inflammatory Actions of Exercise Training.” American Journal of Lifestyle Medicine 1 (3): 220-235. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4243532/.
Klein, A.V., and H. Kiat. 2015. “Detox Diets for Toxin Elimination and Weight Management: A Critical Review of the Evidence.” Journal of Human Nutrition and Dietetics 28 (6): 675-686. https://doi.org/10.1111/jhn.12286.
Schröder, J., and J. Harder. 2006. “Antimicrobial Skin Peptides and Proteins.” Cellular and Molecular Life Sciences 63 (4): 469-486.
Sears, M., and S. Genuis. 2012. “Environmental Determinants of Chronic Disease and Medical Approaches: Recognition, Avoidance, Supportive Therapy, and Detoxification.” Journal of Environmental and Public Health, Article ID 356798. https://doi.org/10.1155/2012/356798.
Tabas, I., and C.K. Glass. 2013. “Anti-Inflammatory Therapy in Chronic Disease: Challenges and Opportunities.” Science 339 (6116): 166-172. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3608517/
Watabe, A., T. Sugawara, K. Kikuchi, K. Yamasaki, S. Sakai, and S. Aiba. 2013. “Sweat Constitutes Several Natural Moisturizing Factors, Lactate, Urea, Sodium, and Potassium.” Journal of Dermatological Science 72 (2): 177-182.