Can sunlight lower your blood pressure?

While limiting sunlight is important in preventing skin cancer, new research suggests that too little of exposure may be harmful for the heart.

According to a study in the Journal of Investigative Dermatology, as little as 20 minutes of ultraviolet (UVA) light can lower blood pressure by a small, but significant amount.

Researchers exposed the skin of 24 healthy individuals to a tanning lamp, over two 20 minute sessions. In the first session, the participants were exposed to both UVA rays and the heat of the lamps, while in the second session the UVA rays were blocked.

The results revealed that the UVA exposure widened the participants’ blood vessels, which in turn lowered blood pressure.

Normal blood pressure can help prevent heart failure, stroke and other cardiovascular diseases, which account for 30 percent of deaths globally each year, according to the World Health Organization.

While it’s still unclear exactly how sunlight lowers blood pressure, the researchers suggest that a compound called nitric oxide plays a role.

“Nitric oxide, along with its breakdown products, known to be abundant in skin, is involved in the regulation of blood pressure,” said lead researcher Martin Feelisch, in a news release. “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.”

Further studies are needed to confirm this hypothesis, but there are other ways to help maintain normal blood pressure, says Dr. Allison Benthal, an internal medicine physician with Advocate Medical Group.

“Healthy lifestyle changes are an important first step for lowering blood pressure,” says Dr. Benthal. “Be sure to get regular exercise, follow a healthy diet, quit smoking and learn to manage your stress.”