If you are not afraid of tanning, can you avoid sunscreen?

NO, the core meaning of sun protection is to prevent sun damage, and tanning is only one of the many manifestations of sun damage.

Let’s simulate what will happen if you don’t wear sunscreen and are exposed to the sun.

5 minutes later:

You start to feel a slight heat on your skin, but it doesn’t seem to change for the time being.
This is because the infrared rays in the sunlight have a thermal effect, and infrared rays can make objects heat up, similar to microwave ovens.

10 minutes later:

Your face begins to feel a distinct burning sensation, with a slight localized redness on your face.
This is because the facial skin belongs to a relatively fragile skin area, and the tactile nerves distributed are also more delicate, and localized redness is caused by irritating erythema caused by direct sunlight, which can usually subside by resting in a cool place for a while. .

After 20 minutes:

Your facial redness begins to intensify, the redness spreads over the entire face, and there is a slight tingling sensation on the face.
This is an important signal of the reduced function of the stratum corneum of the facial skin. Your skin is being damaged by direct sunlight, especially sensitive skin. Because the skin barrier of sensitive skin is thinner than other skin types, the performance in this regard will be The reaction is more obvious than other skin types.

After 40 minutes:

Your face begins to itch and tingle, the skin all over your body begins to turn red, and the function of the stratum corneum decreases.
At this time, the skin begins to produce the phenomenon of ultraviolet allergy. Ultraviolet allergy is an abnormal photoallergic reaction caused by sunlight acting on the human body. In short, it is an immune response.
There are a small amount of light-sensitive substances in our skin, and the amount varies from person to person, and these light-sensitive substances will start to react after being exposed to a certain degree of ultraviolet light.
So when ultraviolet rays act on the surface of our skin, the light-sensitive substances react, causing the diameter of the capillaries to increase, and the skin produces specific inflammation, and you will feel tingling and itching.

After 2 hours:

Your skin is dry, hot, painful, and visibly red and swollen.
At this time, the skin is already in a very serious dehydration state, and it is also the most common situation we encounter when we go out to play at the beach. The common sunburn symptoms when we go to the beach for swimming and vacation are already moderate sunburn.

After 12 hours:

Your skin starts to peel, accompanied by a burning sensation.
This is because the skin cells absorb too much heat, some skin cells are damaged and necrotic, and the necrotic tissue in the upper part of the epidermis accumulates, which will produce the phenomenon of “molding”.

After 24 hours:

The redness of the skin began to subside slowly. After subsiding, the original skin was no longer fair, and the irradiated skin turned black.
This is because ultraviolet rays have the effect of proliferation and activation of melanocytes in our epidermis, so after sun exposure, due to the proliferation and activation of melanocytes, the production of melanin increases, and the skin exposed to ultraviolet rays will appear hyperpigmentation, resulting in hyperpigmentation. Darkening of the skin, which is very noticeable as the redness fades away.

Do you dare not wear sunscreen when you see this?

If you take a fluke and say, then I will not be stupid enough to be exposed to the sun every day, and I go out to a shady place, then you are wrong.

Worse than sunburn is photoaging.

What is photoaging?
Skin aging caused by exposure to sunlight and ultraviolet rays is collectively referred to as photoaging.

As a kind of light with scattering, reflection and refraction characteristics, ultraviolet rays are unfortunately not only present in the sunlight you see with the naked eye, but also exist in the shade.

Our skin is divided into three layers : epidermis, dermis, subcutaneous tissue ( fat and blood vessels , nerves ), and skin is one of the first parts of the human body to age.

Collagen , elastin and other fibers in the dermis work together to form a “spring scaffold”, and medium-wave and long-wave ultraviolet rays have a greater impact on the skin.

When UV rays reach the skin, 70% are absorbed by the outermost stratum corneum of the epidermis, 20% reach the lower layer of the epidermis, and 10% penetrate the epidermis and reach the upper layer of the dermis.

The role of ultraviolet rays is one of the “culprits” that cause skin sunburn and tanning, and then aging.

Skin aging is mainly divided into two forms: natural aging and photoaging , and the characteristics of photoaging and natural aging are different.

The consequences of photoaging include 11 problems such as deep wrinkles, pigmentation, poor skin tone, and precancerous lesions;
There are only three consequences of natural aging: fine lines, sagging, and benign tumors.

Photoaging is very common, especially in the case of strong light exposure, our face is prone to wrinkles, just like some plateau residents or people who work outdoors for a long time, the appearance of crow’s feet or laugh lines is much higher than that of ordinary people. .

Compared with natural aging, photoaging is more likely to cause problems such as precancerous lesions, leather-like appearance and elastic tissue degeneration, and it is more likely to cause various tumors of the skin,

Such as: solar keratosis, squamous cell carcinoma , melanoma , etc.

The more famous case is chronic photoaging in the New England Medicine. I believe that many people have talked about it and I will not say more.

Let’s take a more typical one.

At the opening of the 2012 London Olympics, Bill Gates’ photos of watching the game became a hot topic of discussion at the time. Gates, who was not in his sixties, seemed to have entered a state of aging ahead of schedule.

Gates’ facial skin has shown typical photoaging symptoms – deep wrinkles, uneven skin tone, and pigmentation spots . Of course, this is closely related to the European and American people’s enthusiasm for sunbathing.

Some netizens also posted comparative photos of Gates over the years to show how old Gates is. Those who are interested can search for it themselves.

Therefore, photoaging is a slow process. The primary purpose of our sun protection is not to prevent “tanning”, but to prevent “aging” . Everyone should pay attention to sun protection. It is best to wear dark clothes, because ultraviolet rays are easier to penetrate light. color clothes.

From 10:00 am to 3:00 pm, when the sun is the most intense, don’t go out if you can’t go out, even if it is cloudy or rainy, because long-wave ultraviolet rays can penetrate the clouds and irradiate into the dermis.

Finally, thank you for watching. If you find it helpful, why not give it a like?

Source: Zhihu www.zhihu.com

Author: Diego

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