You may have heard that sunscreen can help protect our skin from sunburn as well as skin cancer. According to a new study, it may also lead to healthier blood vessels.
How is sunshine related to vascular health?
Blood vessels in the skin are vital to prevent us from heat stress through a process called vasodilation which can reduce the heat when the skin is overheating.
During this process, an important signaling molecule, nitric oxide (NO), functions as a vasodilator. When needed, NO triggers relaxation in the smooth muscles around blood vessels to increase blood flow, thus accelerating heat loss.
Every type of skin cell can produce NO, but the cells can only produce with a chemical called 5-methyltetrahydrofolate (5-MTHF), which makes the levels of 5-MTHF essential to the heat loss process in the skin.
Scientists believe that ultraviolet radiation (UVR) from the sun can reduce the levels of 5-MTHF, thus limiting vasodilation and influencing vascular health in the skin.
Scientists consider NO-associated vasodilation as the reflection of vascular health.
How is the study carried out?
Researchers from Pennsylvania State University recruited 13 healthy participants with light-to-medium skin tone. The young adults were exposed to UVR on three different sites of their bodies:
Group 1: One site received UVR only.
Group 2: A second site received UVR with a chemical sunscreen on the skin.
Group 3: A third site received UVR with simulated sweat on the skin.
The dosage of UVR was roughly equivalent of spending an hour outside on a sunny day without the reddening of sunburn.
What’s the result?
Both the sunscreen (Group 2) and sweat testing areas (Group 3) did not show a reduction in NO-associated vasodilation.
By comparison, the UVR-only test site (Group 1) showed reduced NO-associated vasodilation, which means UVR did prevent NO from triggering the relaxation of the muscles around blood vessels.
Researchers also found that compared with the UVR-only and the sweat-treated group, the sunscreen-treated group showed a boosting of vasodilation.
“For those who spend a lot of time working, exercising, or participating in other various activities outdoors, using sunscreen may protect not only against skin cancer but also against reductions in skin vascular function.” Said the lead author S. Tony Wolf.
So, what kind of sunscreen should I use?
According to American Academy of Dermatology (AAD), these phrases appeared on a sunscreen label mean a good-quality sunscreen:
Broad spectrum. This means the sunscreen can protect your skin from both types of harmful UV rays: UVA rays and UVB rays.
SPF 30 or higher. A sunscreen with a SPF rating 30 or higher is recommended to protect your skin better.
Water resistant. This means the sunscreen will stay on wet or sweaty skin for a while before you need to reapply. Usually the sunscreen can stay for 40 or 80 minutes.
When you purchase your sunscreen, remember to look for words on the labels related to your skin condition. For example, you can find “moisturizing” or “for dry skin” words for dry skin. Ask the shop assistant for help if you are not sure what the label means.
What’s the correct way to apply sunscreen?
After choosing your sunscreen, it’s time to apply the sunscreen on your skin. Here are some tips for you:
Apply sunscreen generously before going outdoors. It takes approximately 15 minutes for your skin to absorb the sunscreen. So leave 15 minutes before going out for your skin to be fully protected.
Apply enough sunscreen to cover all exposed skin. Most adults need about 1 ounce, or enough to fill a shot glass of sunscreen to fully cover the body.
Apply sunscreen to all bare skin. You may have get used to applying sunscreen to your face and neck, but don’t forget to also apply to your ears, tops of your feet, arms and legs. If you are going to apply to hard-to-reach areas like your back, ask someone to help you or use a spray sunscreen.
To remain protected when outdoors, reapply sunscreen every two hours.
Reapply sunscreen immediately after swimming or sweating.