Because the sun’s ultraviolet (UV) rays encourage skin cells to divide, while the heat causes them to dry out and die. Thus, a thicker layer of dead cells is formed that ends up peeling off. “The sun just speeds up the skin’s natural process. We are always peeling little by little and, even without us realizing it, the skin renews itself, on average, every 15 days”, says dermatologist Guilherme de Almeida, from Hospital Sírio Libanês, in São Paulo. The effect of the sun lasts for a week, so it takes a few days for the person to peel after getting a tan. The faster proliferation of cells also explains why the greatest danger from the sun is skin cancer. “Younger people manage to protect themselves against mutations in the DNA, but over time mutations can happen, causing cancer”, says Guilherme.
To avoid the “snake effect” of peeling, the way is to be careful with sun exposure, preferring to enjoy the beach and pool, for example, before 10 am and after 4 pm, when UV rays are weaker. Using a sunscreen before sunbathing and a moisturizing cream afterwards also helps to prevent the skin from peeling so much.
1. Human skin is made up of three main layers. The reactions that lead to desquamation occur in the most superficial layer, the so-called epidermis.
2. The epidermis has many cells. The so-called basal cells, are always dividing to form the spinous cells, which are naturally pushed upwards, transforming into granulosa cells, which are flatter. These, in turn, gradually die and give rise to an outer layer that protects the skin.
3. The ultraviolet rays of the sun that reach the skin penetrate all the cells of the epidermis and reach the part of the DNA that controls their cell division. This stimulates the unbridled multiplication of cells, increasing their number in the epidermis.
4. Parallel to multiplication, many cells die from dehydration due to exposure to sunlight. Thus, the natural process of formation of the layer of dead cells is accelerated, making it thicker. And it is this layer that peels off, making room for new cells.