Originally aired July 11, 2016.
For many, summertime means beach trips, boating and a slew of outdoor activities. It’s a time to get outside and take in the fresh air, but it also means more sun exposure.
"As adults, we don't lay out on a daily basis. We go from the car to the house, and those are little bits of sun that we get everyday," says dermatologist, Dr. Debra Scarlett. "And just like hitting something; you hit something enough times it breaks. That's just like skin cells. If you hit skin cells enough times eventually they will break, the DNA will become abnormal, and a skin cancer can form."
Dr. Scarlett suggests wearing an ounce of sunscreen when fully exposed, which equals about a shot glass-worth of sunscreen. Using a thicker layer of lotion better protects skin, although Dr. Scarlett admits that even she is guilty of not using enough.
There are some misconceptions when it comes to sunscreen. First, sunscreen and sunblock are actually different. Sunscreens are chemicals that absorb UV rays, while sunblock physically blocks the sun from your skin. Broad spectrum sunscreens do both, and protect skin from UVA and UVB rays- unlike some sunblocks and sunscreen. So what's the difference between UVA and UVB?
"UVA and UVB are both different wavelengths of light that reach the earth's surface. So UVA, the easy way to remember is that those are the aging rays and UVB are the burning rays," says Scarlett.
In fact, SPF only refers to UVB rays, or the rays that will give you a sunburn. And a sunscreen with an SPF of 30 isn't twice as protective as a sunscreen that has SPF 15. A sunscreen with SPF 15 will block out around 93-94% of UVB rays, while SPF 30 blocks around 97%.
Although vitamin D can be absorbed from the sun, it might not be as much as you think. "There's a rate limiting factor of vitamin D production from the sun. There's a point where your body becomes saturated and cannot make more," she says.
According to Scarlett, most people hit that limit within five to ten minutes in the sun, although it depends on your skin tone. The lighter your skin, the less time you need in the sun to reach your limit of vitamin D production.
She says one of the best ways to protect yourself from the sun is one of the most obvious: clothing, or physical blockers. "I personally use those as my primary form of sun protection," Scarlett says. "You know, physically blocking; wearing hats, sunglasses, long sleeves. I think that's much better."