In the last post, I made the point that sunlight, through the stimulation of nitric oxide (NO) production in the skin, created a vasodilating effect in healthy volunteers that led to lower blood pressure. It was also noted that the effect of sunlight on blood pressure was not due to vitamin D production and circulation, since there was no change in vitamin D levels during the investigation.
High blood pressure is also known as hypertension, and a recent study from China demonstrates that exposure to sunlight correlates to a lowered risk of that disease. In a randomly selected population of Chinese residents from Macau (where the rate of hypertension is very high), the following risk factors for hypertension were assessed: lack of sunlight exposure, low intake of fish, smoking, obesity and lack of exercise. An average of more than one-half hour of sunlight exposure per day compared to none predicted a 40% reduced risk for hypertension. Oily fish consumption more than four times per week predicted a 60% reduced risk; daily moderate physical activity compared to no physical activity predicted a 20% reduced risk; being obese compared to normal weight predicted 4.6 times the risk of hypertension, and heavy smoking predicted 1.4 times the risk.
Hypertension is a major risk factor for heart and other vascular diseases, which are the number-one killers in western societies. Isn’t it time we made a few lifestyle changes that could profoundly reduce the risk of these diseases? The efforts to Frighten people out of the sunlight, coupled with the move to indoor living, have created unquestionable health disasters. We need to once again learn to enjoy safe, non-burning sun exposure.
 Ke L, Ho J, Feng J, Mpofu E, Dibley MJ, Feng X et al. Modifiable risk factors including sunlight exposure and fish consumption are associated with risk of hypertension in a large representative population from Macau. J Steroid Biochem Mol Biol 2013 Nov 1 [Epub ahead of print].