By Marc Sorenson, EdD Sunlight Institute
High blood pressure (HBP, hypertension) is a plague in our society, with one in three adults in the U.S. having the condition. Although 61,762 people per year die from HBP per se, its influence on other diseases may be more dangerous that HBP itself; it is also implicated in increased risk of death from heart disease, heart failure, other arterial diseases, kidney disease, irregular heart rhythms, osteoporosis, cognitive dysfunction, painful intercourse and stroke. Although textbook theory holds that HBP is regulated by the brain, blood vessels, or kidney, recent evidence suggests that HBP could be regulated in the skin, and that sunlight exposure plays a role in in controlling the condition. The authors of the latest research on this subject (footnote 3) demonstrate that sunlight produces a dilation of the arteries (known as vasodilation) by stimulating the production of Nitric oxide (NO) in the skin. NO is a potent vasodilator, stimulated by the ultraviolet A (UVA) portion of sunlight, and has been known for several years to lower blood pressure. Dr. Oplander and his colleagues wrote the first paper on the UVA and blood pressure in 2009,  showing a dramatic reduction of blood pressure with UVA.
A study from China demonstrates that exposure to sunlight correlates to a lowered risk of HBP. 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. Other factors such as smoking and poor nutrition, are of course very dangerous in producing HBP.
Dr. Grant has estimated that by doubling the dose of sun exposure, 400,000 lives could be saved yearly in the USA, with most of the reduction in mortality due to lives saved by lesser incidence of cancer and cardiovascular disease. HBP, of course is a major player in cardiovascular disease, and we know that regular sunlight exposure is associated with profoundly lower risk of about 18 major cancers. Do not neglect to get your regular, non-burning sun exposure. It could save your life!
 American Heart Association/American Stroke Association Statistical Fact Sheet/2013 update.
 Ann Pietrangelo. Healthline 2014 http://www.healthline.com/health/high-blood-pressure-hypertension/effect-on-body (accessed January 4, 2016).
 Johnson RS, Titze J, Weller R. Cutaneous control of blood pressure. Curr Opin Nephrol Hypertens. 2016;Jan25(1):11-5.
 Opländer C, Volkmar CM, Paunel-Görgülü A, van Faassen EE, Heiss C, Kelm M, Halmer D, Mürtz M, Pallua N, Suschek CV.. Whole body UVA irradiation lowers systemic blood pressure by release of nitric oxide from intracutaneous photolabile nitric oxide derivates. Circ Res. 2009;105:1031–40.
 Ke L, Ho J, Feng J, Mpofu E, Dibley MJ, Feng X, Van F, Leong S, Lau W, Lueng P, Kowk C, Li Y, Mason RS, Brock KE. 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].
 Grant, W. In defense of the sun: An estimate of changes in mortality rates in the United States if mean serum 25-hydroxyvitamin D levels were raised to 45 ng/mL by solar ultraviolet-B irradiance. Dermato-endocrinology 2009;4:207-214.