May 8, 2013
Sunlight Lowers Blood Pressure, Benefits May Outweigh Cancer Risk
Brett Smith for redOrbit.com - Your Universe Online
Now that the days are getting longer and longer across North America, there´s no excuse for not going outside and getting a little sun.
According to a new study by researchers from the University of Edinburgh, exposing the skin to sunlight can lower blood pressure, effectively reducing the risk of stroke, heart attack and cardiovascular disease.
The researchers said the blood pressure benefits of getting moderate sunlight most likely outweigh any negative effects of exposing the skin to UV rays.
"We suspect that the benefits to heart health of sunlight will outweigh the risk of skin cancer,” said Dr. Richard Weller, a dermatology researcher at the University of Edinburgh.
In the study, the scientists measured the blood pressure of 24 participants who sat beneath tanning lamps for two, 20-minute sessions. During one session, the participants were exposed to both the UV rays and warming effect of the lamps. For the second session, the volunteers were only exposed to the heat of the lamps.
An analysis of the data showed blood pressure was considerably reduced for one hour after the exposure to UV rays, but not following the heat-only exposure. According to the researchers, the results demonstrate the UV rays are the source of sunlight´s health benefits. They also noted volunteers' vitamin D levels remained the same for both sessions.
The researchers noted nitric oxide production in the skin is solely responsible for the reduction in blood pressure and it is distinct from the body's synthesis of vitamin D. Weller said the study demonstrates the direct correlation between UV rays and lower blood pressure levels.
“The work we have done provides a mechanism that might account for this, and also explains why dietary vitamin D supplements alone will not be able to compensate for lack of sunlight,” he said.
The dermatologist added his future studies will focus on a cost-benefit analysis of exposing the sun to UV radiation.
"We now plan to look at the relative risks of heart disease and skin cancer in people who have received different amounts of sun exposure,” he said. “If this confirms that sunlight reduces the death rate from all causes, we will need to reconsider our advice on sun exposure."
The researchers are expected to present their findings this Friday in Edinburgh at the International Investigative Dermatology (IID) conference, which began on Wednesday and extends through Saturday.
The conference coincides with Skin Cancer Awareness Month — a nationwide, multi-organizational campaign designed to raise awareness of the disease.
Skin cancer is the most common form of cancer diagnosis in the US, with more than 3.5 million new cases annually, surpassing breast, prostate and colon cancers combined, according to the American Cancer Society.
While skin cancer appears most frequently on areas of the skin that are often exposed to the sun, a less common form of the disease known as melanoma can develop anywhere on the body. “¯In men, it typically appears on the torso, head or neck, and in women, on the lower legs. “¯It often appears as a large brown spot that changes color, size or texture, and has irregular borders.