Exposure to Sunlight May Help Lower Blood Pressure

Direct exposure to sunlight may help lower a person's blood pressure and a recent study has tried to explain why this is so.

New research tried to explain previous observations that people's blood pressures are much lower during the summer months than in the winter. What they found is that nitric oxide stored in the upper layers of the skin reacts to sunlight and causes blood vessels to widen as the oxide moves to the bloodstream. This in turn, helps lower blood pressure.

"This is an unexpected finding, in that the skin has not been considered to be involved in blood pressure regulation," Martin Feelisch, lead author of the study and a professor of experimental medicine and integrative biology at the University of Southampton said. However, Feelisch and his colleagues noted that their study only involved healthy young adults so it is unclear whether the effects will be similar among other groups at risk of complications of high blood pressure.

Among people with normal blood pressure, the effect of ultraviolet light is modest, thus resulting to a dropp in blood pressure of between two to five millimeters of mercury. "This is a mild effect. But if you repeat this study in people with high blood pressure, I would predict you will see a more substantial drop." Feelisch also clarifies that the findings of their study do not suggest that people should expose themselves to direct sunlight for very long hours without using sunblock. Rather, they simply recommend a moderate amount of exposure outdoors.

"People are dying of skin cancer and sunlight is the only known risk factor that contributes to skin cancer. We are fully aware of that and don't say everyone should get as much sun as possible. There is a very real risk - but so is the risk for heart disease. One of the main contributors to the disease is high blood pressure."