Associated with sport, sauna or detox cures, perspiration is often presented as a natural means of purifying the body. But is this really the case? Dr. Gérald Kierzek, emergency doctor and medical director of True Medical, takes stock.
Sweat, a survival mechanism above all
First idea received to deconstruct: sweat is not designed to clean the body. “”Sweating is mainly a thermoregulation mechanism, designed to cool the body. It is not the main system of waste elimination, role devolved to liver and kidneys“Explains Dr. Kierzek.
It consists almost exclusively of water, 99 %. The rest is made up of “Electrolytes: sodium and chlorine, responsible for its salty taste. Also potassium, calcium, magnesium“. Sweat also contains a little urea,”It is a waste of protein metabolism, concentration in sweat is low“, lactate produced by muscles during effort and”Traces of other substances: ammonia, glucose, ethanol (after consumption of alcohol, but elimination is negligible), heavy metals (such as lead, cadmium) in tiny quantities and not significant for a ‘detoxification’“, Specifies Dr. Gérald Kierzek.
Sweat to eliminate toxins, a “well -sold” myth
But then, sport or sauna really allow to expel toxins? The doctor’s response is clear: “Not significantly“.
The doctor insists: “The term ‘toxins’ is not scientific, it does not mean anything. If we are talking about real metabolic waste (such as those filtered by kidneys) or environmental pollutants (pesticides, endocrine disruptors), perspiration plays a negligible role“.
In reality, it is the liver is the kidneys that participate the most: “The liver transforms toxic substances into harmless compounds, and the kidneys filter them with blood to excrete them in the urine. It is the most effective and essential system“.
As for persistent substances such as BPC or dioxins, “Studies show that for the vast majority of persistent toxic substances, quantities excreted in sweat are extremely low, much lower than those eliminated by stool and urine“.
The real benefits of perspiration
Even if it does not eliminate toxins, transpiring is nonetheless beneficial. “”Even if it does not eliminate toxins, perspiration is a sign of beneficial health activities. Its benefits are indirect, but very real“, nuance Dr. Kierzek. Here are some advantages to perspiration:
- Body temperature regulation: “”It helps maintain a stable internal temperature during effort or in case of heat, protecting your organs and your vital functions. It is an essential physiological function for survival“;
- Cardiovascular health improvement: “”Sweating is often the result of physical exercise. This exercise strengthens the heart, improves blood circulation and lowers blood pressure“;
- “Well-being” effect and stress reduction: “”The exercise stimulates the release of endorphins, the hormones of well-being. The sauna (which causes passive perspiration) induces deep relaxation and can help reduce cortisol level (stress hormone)“;
- Skin cleaning: “”Sweating helps to rid the skin of impurities and bacteria that are on the surface of the pores. It also hydrates the surface of the skin. Please note: you have to rinse after sweating to prevent salt and impurities from staying on the surface and cause irritation“;
- Reinforcement of the immune system: “”Physical activity that brings together stimulates the immune system. In addition, some studies suggest that the rise in body temperature induced by the sauna (light hyperthermia) could imitate a feverish state and thus strengthen the defenses“;
- Improvement of muscle recovery: “”The increase in blood circulation during and after the effort (which is accompanied by perspiration) promotes the contribution of nutrients to the muscles and the evacuation of waste such as lactate, thus helping better recovery“.
So why does the image of “purifying” sweat continue? Dr. Kierzek is categorical: “Being sweating (sport, sauna) is excellent for health for many reasons, but the idea that we purify his body of his toxins by sweating is a myth. It is a frequent marketing argument to sell detox cures, sweating clothes, etc. Your body is permanently detoxified and effectively thanks to your organs, provided you keep them healthy thanks to a balanced diet and sufficient hydration“.