Why does the skin need protection all year round

Many people have had similar experiences. In winter, the warm sunshine shines on my face, and I think to myself, such a gentle sun, I don't need sunscreen. Or sitting at the window workstation in the office all day, feeling that since I haven't gone out, my skin should be very safe. Or when going out on a cloudy day and seeing thick clouds, one may assume that ultraviolet rays cannot penetrate. These scenes may seem ordinary, but they can easily relax one's vigilance towards skin protection.

In fact, skin protection is not exclusive to summer or outdoor activities. It has no simple correspondence with temperature, season, weather, or even whether one is going out. What truly needs to be vigilant is the invisible ultraviolet rays, as well as broader daily environmental factors such as blue light and air pollution.

Sunscreen is never about the heat of sunlight, but about ultraviolet rays. There are two main types of ultraviolet radiation that are most closely related to skin damage: UVB and UVA. UVB belongs to the category of medium wave ultraviolet radiation, with moderate penetration ability, and is the culprit of skin redness and sunburn. Its intensity does indeed vary with the seasons, with the strongest in summer and weaker in winter. But UVA is completely different. UVA is long wave ultraviolet radiation with extremely strong penetration, which can directly reach the dermis layer of the skin, destroy collagen and elastin fibers, and is closely related to skin sagging, wrinkles, and pigmentation. More importantly, the intensity of UVA remains relatively stable throughout the year. The UVA intensity at noon in winter can still reach 60% to 80% of that in summer. That is to say, even in the cold winter, the factors that cause the skin to quietly age still exist.

Many people think that wearing more clothes and going out less in winter is safe, but the reality is not like that. Even on cloudy days, up to 80% of ultraviolet rays can penetrate clouds and reach the ground. Clouds can block some visible light, but it is difficult to block UVA. Ordinary glass can block most UVB rays and has almost no blocking effect on UVA rays. Therefore, in indoor and car environments near windows, ultraviolet rays can still reach the skin. If you sit at a window station for several hours every day, or stay in the car for a long time during commuting, your skin will also be continuously affected by ultraviolet radiation. Snow environments require more attention. In winter, when skiing or walking in the snow, the snow will reflect more than 80% of ultraviolet rays, and the skin will be exposed to both direct and reflected radiation. The intensity of ultraviolet rays may even exceed that of summer.

The condition of the skin itself during winter also makes protection more important. Low temperature and humidity can lead to a decrease in skin barrier function, reduced sebum secretion, and thinning of natural protective film. The skin's ability to repair also decreases during this season, and once damaged by ultraviolet radiation, the self repair speed is much slower than in summer. The same intensity of ultraviolet radiation may actually cause greater damage to the skin in winter.

If there is still a chance for tanning to turn white, then the damage caused by photoaging is almost irreversible. At present, it is believed that ultraviolet rays in sunlight are the main factor causing skin photoaging. UVA can penetrate deep into the skin, damaging collagen and elastin fibers in the dermis, making the skin rough, wrinkled, and sagging. Studies have shown that 90% of exogenous skin aging is caused by ultraviolet radiation. The photoaging caused by sunlight is the main cause of skin aging. And this kind of damage is cumulative. Sunbathing a little today and a little tomorrow may not show any significant changes in the short term, but in a few years, the difference between long-term sun protection and never sun protection will be very noticeable.

A 52 week experiment found that women who consistently use sunscreen daily improved their skin texture, transparency, and pigmentation by an average of 40% to 52%, and parameters such as crow's feet and skin tone uniformity also improved by 18% to 34%. Another study lasting 4.5 years showed that people who consistently use sunscreen every day did not experience significant skin aging; And for those who choose sunscreen based on their mood, the degree of skin aging is 24% higher.

If in the past we discussed whether or not to use sunscreen, today's more noteworthy issue is that the scope of protection has far exceeded ultraviolet radiation. In addition to ultraviolet radiation, modern people's skin also faces the dual challenges of blue light and air pollution. Blue light comes from the sun, as well as from the mobile phones and computer screens that we cannot do without every day. Research has found that the impact of visible light on the skin is similar to that of UVA. Blue light may be associated with oxidative stress, pigmentation, and photoaging. Although the blue light exposure dose of electronic device screens is usually small, considering the long time modern people spend facing screens every day, the cumulative effect cannot be ignored.

Air pollution is another invisible skin threat. Indoor and outdoor pollutants can stimulate skin inflammation, reduce antioxidant substances in the skin, damage DNA, lead to collagen breakdown, and affect the protective function of the skin. Studies have shown that pollutants in air pollution and ultraviolet radiation can exacerbate each other, causing double the damage to the skin. This is also why today's protective products are no longer just sunscreen, they often undertake multiple tasks such as isolating pollution and resisting blue light. Protection has become a more comprehensive and three-dimensional concept.

Sunscreen is not exclusive to summer, sunny days, or outdoor activities. UVA is available year-round and can penetrate clouds, glass, and many people's cognitive blind spots, accumulating damage to the skin day after day. Blue light and air pollution have added new challenges beyond ultraviolet radiation. Protection is not a seasonal ritual, but a yearly habit. It's not the anxiety of getting tanned, but the most basic respect for skin health. Whether it's spring, summer, autumn, winter, sunny or cloudy days, indoors or outdoors, give your skin a year-round protection. Skin aging is irreversible, but protection is never too late.