We all know how important sunscreen is – it protects us against skin cancer. If that wasn’t enough to convince people, a new study has found that sunscreen also protects the skin's blood vessel function from harmful ultraviolet radiation (UVR) exposure by protecting dilation of the blood vessels while the skin perspiration may also provide protection to the skin's blood vessels from sun damage. The UVR reflecting from the sun have been well documented as a contributing factor to skin cancer and premature skin aging, research has also link it to reducing nitric oxide-associated dilation of skin blood vessels (vasodilation) by decreasing the amount of nitric oxide available in the skin.
Nitric oxide is a compound essential for blood vessel health. The vasodilation of the skin's blood vessels plays an important role in regulating body temperature and responding to heat stress, both locally in the skin and throughout the body.
For the study, researchers from the Pennsylvania State University examined impact of UVR exposure with sunscreen or sweat on nitric oxide's ability to promote vasodilation of skin blood vessels. They exposed healthy young adults with light-to-medium skin tones, to UVR on one arm. The second arm served as control – it did not receive UVR. The UV dosage was equivalent of spending an hour outside on a sunny day.
Researchers assigned three sites on the UVR-exposed arm of each participant to three treatments: the first one received only UVAR, second received UVAR with a chemical sunscreen and the third got UVR with simulated sweat. Results showed that the site that only received UVR had less nitric oxide-associated vasodilation than in the control arm while the second and third sites did not show these reductions in nitric oxide-associated vasodilation.
"Further, when sunscreen was applied prior to UVR, UVR exposure actually augmented [nitric oxide-associated vasodilation] compared to [the control arm], or when sweat was on the skin," the research team wrote. "The presence of sunscreen or sweat on the skin may play a protective role against this effect [of UVR]. 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," wrote author of the study, S Tony Wolf.