Здоровье и благополучие
май 16, 2018
Sun protection is the single most important thing you can do at any age to keep skin healthy
When it comes to aging, skin shows some of the most visible signs. Wrinkles, thinning and sagging skin, and sun spots known collectively as photoaging have all led to explosive growth in the global anti-aging skin care market.
In addition, according to the Skin Cancer Foundation, one in five Americans will develop skin cancer by the age of 70. The good news is that both photoaging and skin cancer risk can be decreased significantly with three simple steps: reducing sun exposure, improving your diet, and choosing well-researched skin care products with clinically supported active ingredients.
According to San Francisco dermatologist Dr. Kathleen Welsh, sun protection is the single most important thing you can do at any age to keep skin healthy, and most people do a poor or incomplete job.
Here comes the sun
The sun emits two types of ultraviolet radiation that reach the Earth: UVA and UVB, both of which damage DNA in the skin. UV rays can lead to skin cancer and accelerate the loss of collagen, which naturally begins to decrease by approximately 1% per year starting at age 20, according to Welsh.
UVA rays, which make up 95% of our exposure, are less intense, so they cause tanning (which is actually a protective response), not burning. They penetrate deeper into the skin, where wrinkles are formed, and they contribute significantly more to photoaging by causing the breakdown of both collagen (a protein that keeps skin firm and youthful) and elastin (a protein that keeps skin bouncy and flexible). UVA can penetrate clouds and glass and is present during all daylight hours year-round. Tanning booths emit UVA rays that are 12 times more potent than those from the sun, so they are especially damaging when it comes to skin health.
UVB rays penetrate less deeply but are more intense, cause skin burning and play a key role in skin cancer. UVB rays are of greatest concern between 10 a.m. and 4 p.m. and vary by season (they are strongest from April to October) and location (the Environmental Protection Agency has an online tool to identify UV risk by location, even broken down by hour of day).
According to the Skin Cancer Foundation, an estimated 90% of non-melanoma skin cancers and 90% of skin aging are caused by sun exposure, the majority of which occurs during normal daily activity, not lounging on the beach.
The American Academy of Dermatology recommends staying in the shade whenever possible, wearing protective clothing and applying a broad-spectrum (which means it blocks both UVA and UVB rays) sunscreen of SPF 30 or higher to all areas of the body that are exposed to the sun. Sunscreen should be applied 15 to 30 minutes before sun exposure and reapplied every two to four hours during sun exposure, according to Welsh. In addition, she always recommends big hats and sunglasses and using UV-tinted windows in your car that block up to 99.9% of UVA rays.