How to cleanse your skin after sports?

Engaging in sports can be a way to tone one's body. However, after a physical exercise session, changes can be observed on our skin. It is because of these changes that post-exercise cleansing can prove to be fundamental.

Reason #1: The sweat produced during exercise can be odorous.

Indeed, during physical activity, our sweat rate can increase compared to when we are at rest. In a study conducted by Lindsay R. KALAN and her team, researchers found that certain microorganisms showed particular preferences for sweat: this is the case for the commensal bacteria of the skin Staphylococcus epidermidis, typical of the skin flora of a healthy microbiota. However, in another study led by Niranjan NAGARAJAN, the results showed that different bacteria, including Staphylococcus epidermidis, could produce bad odors.

Metabolic pathway analysis has revealed the production of isovaleric and acetic acid, responsible for a sour smell, by the enriched enzymes of S. epidermidis and a production of sulfur by the species of Staphylococcus, by breaking down certain constituents of sweat such as amino acids and fatty acids. Therefore, washing the skin after sports will help to eliminate sweat and the associated characteristic odor.

Reason #2: Sweat can cause itching in some individuals.

Sweat can sometimes cause itching, particularly in individuals suffering from atopic dermatitis. It is hypothesized that a component of sweat that induces itching is highly concentrated in the sweat of people with atopic dermatitis. Therefore, the properties of sweat were compared between subjects with atopic dermatitis and healthy subjects after perspiring in a sauna.

In the sweat of individuals with atopic dermatitis, the concentration of LL-37, an antimicrobial peptide, varied from one person to another. As LL-37 is recognized as being cytotoxic, it can be hypothesized that sweat containing high concentrations of LL-37 might promote inflammation and itching in individuals suffering from eczema.

Furthermore, sweat retention due to the occlusion of sweat pores has been reported in atopic dermatitis. The occlusion of sweat pores is supposedly due to biofilms of Staphylococcus epidermidis. Skin dryness and the increase in skin temperature due to sweat retention may partly contribute to the worsening of itchiness in atopic dermatitis. However, the scientific evidence is still weak for this latter hypothesis.

Furthermore, the epidermis has para-cellular tight junctions that act as a barrier to regulate skin permeability. A decrease in their expression leads to water leakage out of the body, which causes skin dryness, the penetration of pathogenic agents, and skin inflammation.

Studies have shown that dermcidin, an antimicrobial peptide found exclusively in sweat, is located not only within the sweat glands but also in the outer tissues in lesions of atopic dermatitis, suggesting that sweat could infiltrate into the tissues.

Sweat contains proteases, histamine, salt, LL-37, and antigens. If it infiltrates the tissues, it can then cause tingling or itching sensations.

Reason #3: The sweat produced by exertion is uncomfortable.

Finally, sweat is simply unpleasant on the skin, it provides a sensation of discomfort. Sticky to the touch, wet appearance of the skin, greasy effect on the hair... washing can therefore help to get rid of this feeling of being "dirty".

After physical exertion, the skin requires a specific cleansing routine. The first thing to do post-workout is topat the skin dry without rubbing to remove excess sweat. Use a clean towel to avoid any contamination.

Next, take a full shower, focusing on the face and skin folds, where sweat tends to accumulate the most. It is recommended to use mild soaps, without harsh ingredients (synthetic fragrances and sulfates), with a physiological pH to avoid disrupting the skin's balance.

Furthermore, it is preferable to wash withlukewarm to cold water to fully enjoy the benefits on the entire body. Indeed, Gareth W. DAVISON and his team found that immersion in cold water reduced delayed onset muscle soreness after exercise, particularly through vasoconstriction that reduces inflammation in muscles that have been exerted during effort.

When should you shower after physical activity?

Several studies have shown that perspiration can continue up to an hour after the end of physical exertion, during rest. This is due to the fact that body temperature, which increases during exercise, continues to be elevated after the effort. The body then produces sweat in an effort to thermoregulate and cool the skin. We therefore advise you to wait at least one hour after exercise before washing to ensure all residual sweat is removed.

• LINDINGER M. I. & al. Sweating rate and sweat composition during exercise and recovery in ambient heat and humidity. Equine Veterinary Journal (1995).

• DAVISON G. W. & al. Cold‐water immersion (cryotherapy) for preventing and treating muscle soreness after exercise. Cochrane Database of Systematic Reviews (2012).

• NAGARAJAN N. & al. Understanding the microbial basis of body odor in pre-pubescent children and teenagers. Microbiome (2018).

• KATAYAMA I. & al. Why does sweat lead to the development of itch in atopic dermatitis? Experimental Dermatology (2019).

• KALAN L.R. & al. Sweat and sebum preferences of the human skin microbiota. Microbiology Spectrum (2023).