Exposing skin to sunlight may help to reduce blood pressure and thus cut the risk of heart attack and stroke. From the January 17, 2014 Science Daily:
Exposing skin to sunlight may help to reduce blood pressure and thus cut the risk of heart attack and stroke, a study published in the Journal of Investigative Dermatology suggests.
Research carried out at the Universities of Southampton and Edinburgh shows that sunlight alters levels of the small messenger molecule, nitric oxide (NO) in the skin and blood, reducing 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."
While limiting sunlight exposure is important to prevent skin cancer, the authors of the study, including Dr Richard Weller of the University of Edinburgh, suggest that minimising exposure may be disadvantageous by increasing the risk of prevalent conditions related to cardiovascular disease.
Cardiovascular disease, often associated with high blood pressure, accounts for 30 per cent of deaths globally each year. Blood pressure and cardiovascular disease are known to vary according to season and latitude, with higher levels observed in winter and in countries further from the equator, where ultraviolet radiation from the sun is lower.