What's the difference between UVA and UVB?
All UV rays are invisible, but there are different types that injure skin in various ways. The two we’re affected by are UVA and UVB (UVC rays don’t make it through the Earth’s atmosphere). “The difference between UVA and UVB rays is the depth they penetrate,” says Jennifer Linder, MD, a Mohs Skin Cancer Surgeon and the chief scientific officer for PCA Skin. UVA rays, also known as aging rays, have a longer wavelength and travel further, Dr. Linder says. Because they reach a deeper skin layer, called the dermis, UVA rays weaken the skin's support structure, causing wrinkles and sagging while also playing a role in cancer formation.
How UV fries your skin
While an energy boost might be good for your workout, the added energy from UV rays causes cell meltdown. When UV rays hit the cell, helpful oxygen molecules produce free radicals that can damage cell function. “The free radicals attack cellular DNA and cause it to break apart or change structure, which could eventually lead...to cancer,” Dr. Christensen says.
Where do cancer cells come from?
Depending on how damaged cells react, sun exposure puts you at risk for several types of skin cancer. The most common (and least deadly) types are basal and squamous carcinoma. These cancers target the keratinocyte cells that make up the outer layer of the skin, Dr. Christensen says. After years of repeated UV damage, the DNA-mutated cells replace healthy cells and become a cancer. Once enough cancer cells are present, the healthy skin in the area can no longer do its job — and the cancer takes over.
Signs you have skin damage
The most obvious evidence that you’ve let UV rays abuse your skin is seeing red — or tan. The swelling and pain from sunburn is an inflammatory response from sun-damaged cells. And, a tan is your body’s way of shielding itself from more UV rays.
How to do damage control
No need to go live in a cave; you can still repair some of your past skin sins and prevent future assaults. The first step? Ditch the idea that the majority of your sun damage happened before you turned 18. “That’s a commonly misquoted idea,” Dr. Wang says. “When you look at sun damage, the results are cumulative, so you haven’t done it all at once, [nor do you] have no hope of stopping it.” In other words, the UV rays you subject your skin to now are just as dangerous as the ones you soaked up years ago.