Why can’t you abuse a hot shower?

After a long day at work, the pinnacle of luxury for some is a long, hot and almost scalding shower. A quarter of an hour, even half an hour is enough to evacuate bodily impurities and worries. But yes, washing at high temperatures is not only bad for energy consumption and the planet. It is also for your body.

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Enemy of heavy feet

Humans manage to maintain a body temperature of about 37°C thanks to brown fat, also called adipose tissue. Circulation works to dissipate this internal heat to the skin and extremities, but the hotter jet of water causes vasodilation, that is, an increase in blood vessel diameter and blood flow. And if the process is normal or even beneficial for oxygen exchange, internal organ discharge and muscle relaxation, it can exacerbate symptoms in people with venous insufficiency, says Sophie Blaise, professor of vascular medicine at Grenoble University Hospital. .

According to the specialist, this condition is most often identified by swelling of the legs (calves, ankles or feet) associated with this well-known feeling of heaviness in the legs or varicose veins or varicose veins of the superficial leg.

“In case of venous insufficiency, the blood stagnates in the veins of the lower limbs. Normally, muscle contraction is involved in returning blood to the heart, but the heat of the shower, associated with the almost stationary position it assumes, will reduce the pressure and thus further limit this venous return,” notes Alain Gelon. , CNRS Research Director.

Dryness and dehydration

The skin is also affected by excess heat. “Beyond 39°C, water gradually melts the outer layer of the epidermis, the “hydrolipid membrane”, whose role is to act as a barrier against external aggression. that Skin microbiota (1).

Without this film, the skin is more easily dehydrated, which explains the feeling of tightness when you get out of the shower. “If excess temperature occurs too often, it can weaken the epidermis and lead to increased sensitivity, which can lead to atopic dermatitis, better known as eczema,” says Alain Gelon. This is why it is important to moisturize the skin with emollient creams when the skin is dry.

Skin microbiota imbalance

Beware of cleaning products in the grooming department. High temperatures combined with cleansing gels rich in preservatives and potentially allergenic texturizing agents will have a cleansing effect on the skin that is detrimental to our skin microbiota. “If 5% of the bacteria are harmful, the majority of them, on the contrary, contribute to protecting the skin from infections by occupying a large amount of space,” explains CNRS research director Alain Gelon. However, hot water will take more part in turning them off one by one. The specialist also reminds that it is important for the body to get used to contact with bacteria from childhood, so that the immune system gets used to the “good” ones and prevents the accumulation of pathogens.

Away from the button, closer to the smells. “You can wash every day,” reassures Alain Gallon, “as long as you don’t overwash, with moderate water and a neutral pH or shower oil without rubbing too much.”

(1) Alain Gelon co-authored with Alexandra Raylan Skin microbiota, Ed. First, 240 pages, €15.95.

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