Does Sunlight Extend Your Life?

Every time you put on sun-block, the sun wells up and sheds a salty, sizzling tear... He's just trying to share his warm, healthy rays with you. And you turn around and accuse him of plotting to give you forehead cancer. Now we've all heard about the dangers of too much UV exposure and no doubt each experienced at least one bad sun burn personally. But what if smearing on the Coppertone and hiding from the sun is actually doing us more harm than good?

Current public health advice to limit sun exposure stems from the undeniable evidence that ultraviolet radiation (UVR) from the sun is a risk factor for non-melanoma and melanoma skin cancers (especially for those delicate powder snowflakes who haven't built up some natural protection). That being said, there is now a growing body of evidence to contend that people who avoid sunlight as well as those living in higher latitudes (higher latitude = lower UVR) have a higher risk of all-cause mortality. In other words... people who get more sun live longer.

​Initially vitamin D (a product of sunlight) was championed as the missing link. But since correcting blood levels of vitamin D through supplementation does not appear to replicate the same effects, researchers were forced to dig deeper.

So what is this mysterious life-giving mana from the sun? Some really brainy dermatologists in Edinborgh think it's Nitric Oxide...

It turns out that human skin contains large stores of nitric oxide precursors. And when UVA* light hits our skin's surface, these precursors form active nitric oxide that is released into our blood stream. This is big news. And perhaps warrants amendments to exposure recommendations considering heart disease is the #1 cause of death in the US and kills 50 times as many people every year as skin cancer (600,000 /yr vs 12,000 /yr).

*UVA = Long Wave Radiation, UVB = Short Wave Radiation
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So there you have it... The sun emits UV rays. When UV rays hit our skin, nitric oxide is released into our circulation. When nitric oxide is released, our blood pressure drops and the inflammation in our blood vessels goes down. When this happens you get to live longer. So take a break from your cubes and go fill your pockets full of sunshine.

For more info, check out Richard Weller's TED Talk: Could the sun be good for your heart?

References and Further Reading:
UVA Irradiation of Human Skin Vasodilates Arterial Vasculature and Lowers Blood Pressure Independently of Nitric Oxide Synthase
http://www.nature.com/jid/journal/v134/n7/abs/jid201427a.html
Is Sunlight Good for our Heart?
http://eurheartj.oxfordjournals.org/content/early/2010/03/09/eurheartj.ehq069.full
Avoidance of Sun-exposure is a Risk Factor for All-cause Mortality
http://www.ncbi.nlm.nih.gov/pubmed/24697969
Sun CAN Actually Help Protect You Against Skin Cancer
http://articles.mercola.com/sites/articles/archive/2011/06/16/sun-can-protect-you-against-skin-cancer.aspx
Sun exposure prior to diagnosis is associated with improved survival in melanoma patients: results from a long-term follow-up study of Italian patients.
http://www.ncbi.nlm.nih.gov/pubmed/18406602?ordinalpos=8&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum