A new study has revealed that exposing skin to sunlight may help to reduce blood pressure and thus cut the risk of heart attack and stroke.

Research carried out at the Universities of Southampton and Edinburgh showed that sunlight alters levels of the small messenger molecule, nitric oxide (NO) in the skin and blood, reducing blood pressure.

Martin Feelisch, Professor of Experimental Medicine and Integrative Biology at the University of Southampton, said: "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, suggested that minimising exposure may be disadvantageous by increasing the risk of prevalent conditions related to cardiovascular disease.

The results suggested that UVA exposure dilates blood vessels, significantly lowers blood pressure, and alters NO metabolite levels in the circulation, without changing vitamin D levels.

Further experiments indicated that pre-formed stores of NO in the upper skin layers are involved in mediating these effects.

The study was published in the Journal of Investigative Dermatology.