Sunlight Exposure may help Lower Blood Pressure

Exposing skin to sunlight changes levels of the messenger molecule nitric oxide in the skin and blood, lowering blood pressure, according to new research from the Universities of Southampton and Edinburgh.

“Nitric oxide along with its breakdown products, known to be abundant in skin, is involved in the regulation of blood pressure,” said University of Southampton professor Martin Feelisch. “When exposed to sunlight, small amounts of nitric oxide 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.”

It is important to limit your sunlight exposure in order to prevent skin cancer. On the other hand, the authors of the study suggest that minimising exposure may also be harmful, by increasing risks of the established conditions related to cardiovascular disease.

High Blood Pressure and Nitric Oxide

Frequently linked with high blood pressure, cardiovascular disease causes 30 per cent of deaths worldwide per year. It is known that blood pressure and cardiovascular disease vary according to season and latitude. Higher levels are seen in winter and in countries further from the equator, where ultraviolet radiation from the sun is lower.

“These results are significant to the ongoing debate about potential health benefits of sunlight and the role of Vitamin D in this process”, Professor Feelisch adds. “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.”

Not to be confused the the gas nitrous oxide, nitric oxide is an important cellular signaling molecule involved in many physiological and pathological processes.

For example, it is a powerful vasodilator with a short half-life of a few seconds in the blood. Long-known pharmaceuticals such as nitroglycerine and amyl nitrite were discovered, more than a century after their first use in medicine, to be active through the mechanism of being precursors to nitric oxide.

“We believe that nitric oxide 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 nitric oxide and deliver it to the circulation more efficiently,” said Professor Feelisch.