As we enter into the new year, it’s never too early to start thinking about the spring — the cool breeze, the blooming flowers, and of course, the warm sunlight. Now, (not like you needed it), scientists have discovered a new reason why sunlight can positively impact your health. According to researchers from the universities of Southampton and Edinburgh, exposure to sunlight can alter the levels of nitric oxide in the skin and blood, reducing the blood pressure and therefore lessening the chances of a heart attack or stroke. The study was published in the Journal of Investigative Dermatology.

"NO [nitric oxide] 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,” said Martin Feelisch, professor of experimental medicine and integrative biology at the University of Southampton.

Nitric oxide, a gas found in the body, is important because its main job is to increase the blood flow by dilating blood vessels. “It's sometimes given in supplement form to heart patients, orally, and intravenously,” according to the Los Angeles Times.  “In at least one study, it's been shown to be effective for lowering blood pressure.”

The study was conducted using 24 healthy volunteers. They were each exposed to ultraviolet light from tanning lamps for two 20-minute sessions. The first 20 minutes, the skin of the volunteers was exposed to both UVA rays and heat from the lamps; in the second 20-minute session, the participants were only exposed to the heat, not the UV rays.

Dr. Richard Weller of the University of Edinburgh believes too much or too little exposure can be a bad thing. Moreover, in the same way overexposure to sunlight can be bad for a person’s health, a lack of sunlight can also be just as detrimental.  

The scientist also believes that the nitric oxide from the skin is a major factor in maintaining a healthy cardiovascular system. More studies are needed to conclusively prove this theory, but this is a good starting point. “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 [nitric oxide] and deliver it to the circulation more efficiently," Feelisch said.

As it is, the Centers for Disease Control and Prevention estimates that stroke is the number four cause of death in the United States. Heart diseases of all kinds resulted in 597,689 deaths in 2010.

Feelisch also add that vitamin D might not be advantageous when maintaining a healthy heart, and it most probably only benefits bone health; the need for minimal sunlight is important for overall health, and as the study suggests, previous thoughts on sun exposure need to be reevaluated. “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,” Feelisch said. 

 

 

Source: Liu D, Fernandez O, Alistar Hamilton. UVA Irradiation of Human Skin Vasodilates Arterial Vasculature and Lowers Blood Pressure Independently of Nitric Oxide Synthase.  Journal of Investigative Dermatology. 2013.