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Sunlight not only contributes to improved moods, it also increases vitamin D levels. In a new study, researchers examined another benefit of sunlight. According to the research team from the Universities of Southampton and Edinburgh, sunlight could help reduce blood pressure levels and lower the risk of heart attack and stroke.

For this small study, the researchers examined skin samples from 24 healthy participants. The volunteers were exposed to two sessions of ultraviolet (UVA) light under tanning lamps for 20 minutes each. In one of the groups, the participants were exposed to both the UVA light and the heat from the lamps. In the other group, the participants were only exposed to the heat.

The researchers discovered that the sunlight was able to change the levels of nitric oxide (NO) in the body. When NO levels were altered, the participants' blood pressure levels were lowered. The researchers believe that the sunlight is capable of dilating blood vessels, which in turn lowers blood pressure.

"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," explained Martin Feelisch, Professor of Experimental Medicine and Integrative Biology at the University of Southampton.

The authors, who included Dr. Richard Weller of the University of Edinburgh, added, "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."

The researchers cautioned that too much sun exposure could lead to skin cancer and therefore, people should remember to applu and reapply sunscreen. The study was published in the Journal of Investigative Dermatology.