A lot of people enjoy spending time outdoors and are not looking forward to hibernating for the next few months of winter. There are actually a lot of important benefits we can reap from this time spent outdoors: the sun keeps us warm, helps plants grow, and stimulates our bodies to produce Vitamin D. However, Dr. Steve Rotter, a dermatologic surgeon in Virginia, claims that “sun is the greatest threat to your skin’s health and youth.” Excessive sun exposure can be dangerous and cause sunburns, premature aging and skin cancer promotion.
There are two relevant types of solar radiation, each with different effects on skin. UVB rays have a shorter wavelength and are less penetrating. These cause the skin to burn and peak at midday. UVA rays, however, have a longer wavelength which allows them to penetrate into the deep layers of the skin. These rays, which are a constant presence all day long, are responsible for the tanning response, carcinogenesis, and aging.
Luckily, sunscreens can protect against both kinds of harmful rays. There are actually two types of sunscreen. One type functions as a physical blocker, and has either zinc oxide or titanium dioxide as its active ingredient. Sunscreens of this type act as a barrier to the UV rays by reflecting and deflecting them. This kind of sunscreen also tends to be thicker and more visible, leaving a white tint on the skin. The second type of sunscreen functions as a chemical blocker. These kinds of sunscreen interact directly with the UV rays, absorbing their energy so that photons of heat are harmlessly dissipated. Thus, they deteriorate faster than physical blockers. They also tend to be more irritating to the skin.
The Sunburn Protection Factor (SPF) is a nonlinear scale which measures the effectiveness of the sunscreen. SPF 15 blocks 93% of UV rays, SPF 30 blocks 97% of UV rays and SPF 50 blocks 98% of UV rays. After that, there isn’t really any significant benefit of using a higher SPF.
Experts recommend applying sunscreen daily, but especially before prolonged exposure. This includes going to the beach, but also when spending time in the snow—water and ice are reflective and actually amplify UV rays. NYC dermatologist Dr. Doris Day cautions that the worst sunburns that she sees actually result from cloudy days when people tend to spend more time outside but skip the sunscreen. However, while clouds block infrared radiation so it doesn’t feel hot, they only block 20% of UV rays, so sunburns are still a risk.
Without proper protection, excessive sun exposure can cause several kinds of skin damage. Many people enjoy looking tan, but clinical professor of dermatology at NYU Medical Center Dr. Darren Rigel explains that, “A tan is literally your body’s response to being injured by UV exposure.” The Skin Cancer Foundation found that there are more people who develop skin cancer because of tanning than people who develop lung cancer because of smoking. There is, in fact, no such thing as a safe tan.
Furthermore, skipping sunscreen in your daily routine foregoes protection against all three types of skin cancer: basal cell carcinoma, squamous cell carcinoma and melanoma. Melanoma is the most deadly of the three: in fact someone dies of it every 52 minutes. Eighty-six percent of melanoma cases are attributed to sun exposure. The risk of contracting melanoma doubles after experiencing more than five sunburns. While darker skinned people are less vulnerable to the UVB rays which cause sunburns, they are still vulnerable to the cancer-promoting UVA rays. Singer Bob Marley famously died of skin cancer, which was initially misdiagnosed as a soccer injury.
If the myriad health risks aren’t enough of a reason to use sunscreen, there are aesthetic reasons too. Sun damage, along with cigarette smoking, is one of the top two causes of premature aging. Chronic sun exposure leads to lack of skin elasticity, colloquially known as saggy skin. One famous study described a man who worked as a truck driver for forty years. Because car windows block UVB (burn rays) but not UVA (aging rays), the left side of his face looked drastically older than the right side. While his right side looked typical for a man of his age, his left side was noticeably saggy and spotted because of his unprotected sun exposure.
The bottom line? Enjoy the sun—but enjoy it with sunscreen!