The Benefits & Cautions of Exposing Your Skin this Spring/Summer.
This article was originally posted in May 2017.
Skin cancer is the most common cancer in the US where 1 in 8 people will get skin cancer in their lifetime and 1 in 50 will get melanoma. This makes skin protection important for everyone. However, sun exposure is tricky … you need sun exposure to make Vitamin D in your skin.
Benefits of Sun Exposure
Exposing 90% or greater of your skin to the sun until you get a Minimal Erythema Dose (MED) will produce around 20,000 IU of Vitamin D in your skin. The MED is how much sun exposure it takes for your skin to turn slightly red. For white skin in the beginning of the season this is about 15–20 minutes. For pigmented skin, it can be up to 45 minutes initially.
Right now, we are experiencing an epidemic in Vitamin D deficiency due to our avoidance of the sun, working indoors, and use of sun blocks/sunscreens that prevent production of Vitamin D in our skin. Low Vitamin D levels have been associated with an increased incidence of many significant diseases. Low D is associated with an increased risk for the following cancers: melanoma, breast cancer, prostate cancer, colon cancer. Low D is also associated with Metabolic Syndrome, chronic inflammation, autoimmune diseases, and increased cardiovascular disease. This is one of the reasons I prefer graded sun exposure with protective covering and limited sun blocks to high risk burn areas. This allows me to produce Vitamin D in my skin, yet prevents excessive sun exposure and sun burns. I will address this as the end of this article.
Think of UVA as the “aging” rays and UVB as the “burning” rays.
Selecting Skin Protection: Sunscreen vs. Sun Block
The best skin protections are those that block both UVA and UVB light from damaging your skin and will last all day without reapplying. Think of UVA as the “aging” rays and UVB as the “burning” rays.
Most sunscreens protect against UVB rays, while not really protecting against UVA. This explains why you can spend the day in the sun and not burn, but notice the freckles on your skin get darker, become more tan/brown or see pigment changes. Additionally, most commercial sunscreens use chemicals that absorb UVA or UVB but which break down over a few hours and no longer work. They also often only block UVA2 and not UVA1 which also can affect your skin.
The best sun protectants are sun blocks that contain titanium dioxide or zinc oxide that is non-micronized. Most people prefer micronized blocks because they absorb into the skin and are therefore less messy, but I do have some concerns with increased absorption of zinc or titanium via the skin. Sun blocks block both UVA1/UVA2 and UVB and, if applied correctly—and if you do not sweat excessively or get into water too much—they can last all day.
- SPF 2 50% 50%
- SPF 10 90% 90%
- SPF 15 93% 93%
- SPF 30 97% 97%
SPF measures only UVB protection, which causes sunburns, but does not reflect UVA protection. UVA exposure has been associated with melanoma and other kinds of skin cancer. A SPF of “2” blocks 50% of UVB radiation, a SPF of “10” blocks 90%, SPF 15 blocks 93% and SPF 30 blocks 97%.
So, you can see that once you get to a SPF of 15 you don’t get much additional sunburn protection. You should look for a product with excellent UVA protection and a SPF of 15–30.
Applying Sun Blocks
When applying sun blocks, you should use one ounce to cover your entire body. The average person uses less than half that amount and so loses some benefit from the lotion. You should also limit sun exposure during the times of day when the amount of UV radiation intensity is the highest, typically 10am – 3pm. For a map of up-to-date UV intensity for your area, visit the EPA site and type in your zip code to learn the UV intensity for your area. If you would like to research sunscreens, here is a great resource from the Environmental Working Group. Or, you may benefit from Karen Reed’s article, Your Absolute Guide to the Best Sunscreen for Sensitive Skin.
The best way to approach sun exposure is through graded exposure and cover up clothing items.
My Personal & Professional Recommendation:
The best way to approach sun exposure is through graded exposure and cover up clothing items. This means is that during the beginning of the spring/summer season you only expose yourself to the sun for a limited amount of time, say 15–20 minutes and use protective clothing to cover up all other times. High risk areas like your face, hands, arms, etc. should have a sun block applied before or after your initial 20-minute exposure—whichever works best for you. This way you get your daily dose of Vitamin D, prevent excessive skin exposure to potential chemicals in skin protection products, and prevent sunburns. As your skin gets accustomed to the sun, you can expose more of your body for longer, always being aware of the Minimal Erythema Dose of sun. This is the amount of sun exposure you need to get slightly red over your exposed areas. Typically for white skin this is 15–20 minutes initially. For pigmented skin, it can be up to 45 minutes initially.
Take care and enjoy the Spring and Summer sun!