Sunlight exposure could help lower blood pressure, which in turn reduces the risk of heart attack and stroke.
New research suggests sunlight affects the levels of the "messenger molecule" nitric oxide (NO) in the skin and blood, this effectively reduces blood pressure, a University of Southampton news release reported.
"NO along with its breakdown products, known to be abundant in skin, is involved in the regulation of blood pressure. When exposed to sunlight, small amounts of NO are transferred from the skin to the circulation, lowering blood vessel tone; as blood pressure drops, so does the risk of heart attack and stroke," Martin Feelisch, Professor of Experimental Medicine and Integrative Biology at the University of Southampton said in the news release.
A healthy balance is important when it comes to sunlight exposure because catching too many rays has been linked to skin cancer. Researchers suggested decreasing sunlight exposure could be "disadvantageous" because of its link to other health consequences, some of which can lead to heart conditions.
Cardiovascular disease (which is often linked to high blood pressure) is responsible for 30 percent of deaths globally every year.
High blood pressure has been known to vary with "season and latitude," and the rates are higher during winter in regions farther away from the equator.
"These results are significant to the ongoing debate about potential health benefits of sunlight and the role of Vitamin D in this process. It may be an opportune time to reassess the risks and benefits of sunlight for human health and to take a fresh look at current public health advice. Avoiding excess sunlight exposure is critical to prevent skin cancer, but not being exposed to it at all, out of fear or as a result of a certain lifestyle, could increase the risk of cardiovascular disease. Perhaps with the exception of bone health, the effects of oral vitamin D supplementation have been disappointing," Professor Feelisch said.
In order to make their findings the team exposed 24 healthy individuals to ultraviolet light from tanning beds over the course of two 20-minute sessions. In another study the volunteers were exposed to only the heat from the tanning lamps.
The team found ultraviolet ray exposure dilates blood vessels, which lowers blood pressure. It also changes NO levels without interfering with vitamin D levels. Levels of NO stored in the upper skin are believed to "mediate" these effects.
"We believe that NO from the skin is an important, so far overlooked contributor to cardiovascular health. In future studies we intend to test whether the effects hold true in a more chronic setting and identify new nutritional strategies targeted at maximizing the skin's ability to store NO and deliver it to the circulation more efficiently," Professor Feelisch said.
