UV exposure directly lowers blood pressure
According to research published in the Journal of Investigative Dermatology, when UV rays reach the skin, a compound that helps lower blood pressure is released into our blood vessels.
The researchers at the University of Edinburgh in the UK postulate that the cardiovascular benefits of vitamin D may outweigh the risks of skin cancer.
The researchers recruited 24 volunteers to sit under sunlamps for two 20 minute sessions while the scientists observed their blood pressure. In the first session, the participants were exposed to UV rays and the heat of the lamp. In the second session the UV was blocked so only the heat was affecting the skin.
The researchers found that the participants’ blood pressure decreased and their heart rate rose in the UV exposure session, but not when they were exposed to the heat only. The reduction in blood pressure lasted for 50 minutes. Vitamin D levels were unaffected in both sessions.
Richard Weller, senior author of the research explains, “We suspect that the benefits to heart health of sunlight will outweigh the risk of skin cancer. 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.”
The researchers plan to focus future research on the risks of heart disease and skin cancer in people with different levels of sun exposure.
He concludes, “If this confirms that sunlight reduces the death rate from all causes, we will need to reconsider our advice on sun exposure.”
Sources
Sun’s blood pressure benefits ‘may outdo cancer risks.’ BBC News. May 7, 2013.
It says that in this experiment that “Vitamin D levels were unaffected in both sessions.” Shouldn’t their Vitamin D levels have changed at least in the 20 minute session directly under the sunlamp? What factor(s) would cause no change?
IAW, good question and sorry for the late response. It looks like they used UVA lamps, so there was no UVB to induce vitamin D synthesis.
Full details on his study, including Ted Talk are at
http://is.gd/uvnitric