By now, you may be yearning for a few cloudy days and cooler temperatures. But there are many good reasons why you should spend some time in the sun during these dog days of summer.
Including a recent study that shows that sunlight can actually lower your blood pressure.
And that’s not all that the golden orb can do for your health. Of course, you already know that sunlight helps your skin activate vitamin D. Which helps with major conditions like depression, dementia, diabetes, and heart disease.
Ironically, the sun’s rays can even lower your risk of cancer, including skin cancer. In a June 25 Daily Dispatch, I reported on a study showing that sunlight actually helps protect even you from the 9 percent of skin cancers that are malignant.
And now there’s the new study about blood pressure. Let’s shed some light on that.
The mental and physical ways sunlight helps lower blood pressure
We know that spending time outdoors has positive mind-body effects—especially for easing stress, which itself helps lower blood pressure. And now, British researchers have found how sun exposure physiologically reduces blood pressure as well.
Scientists have already observed that human blood pressure is commonly higher in winter months, when there is less sun and people don’t go outside as much. So the British researchers channeled the quintessentially English sleuth Sherlock Holmes to discover how these two factors link together.
They found that when sunlight hits our skin, it leads to the release of nitric oxide. They also discovered that human skin contains more nitric oxide than other parts of our bodies.1
This finding is important because nitric oxide helps dilate our blood vessels—which lowers blood pressure. It also reduces adrenalin from nerves that control blood vessels—also lowering BP.
(That’s one reason why nitroglycerin has long been used as a fast, effective treatment for angina. It releases nitric oxide, which causes blood vessels to dilate and pump more blood and oxygen to starving heart muscle tissue.)
Why you need time in the sun without sunscreen
It’s interesting that life could not emerge from the sea onto the land (about 300 million years ago) until there was enough oxygen and ozone in the atmosphere to block the solar radiation that would disrupt DNA—and kill those emerging life forms
But since then, human skin has adapted to use certain wavelengths of this solar radiation—specifically UV rays—to activate molecules that are essential to life and health, like nitric oxide and vitamin D.
This natural prescription for health was known to 19th century physicians, but forgotten during the 20th century. And basically eradicated in the 21st century by the sunscreen industry.
As I wrote in the June 26 Daily Dispatch, a growing number of sunscreens are designed to block UV rays from penetrating your skin. Which, of course, also blocks vitamin D and nitric oxide.
That’s why I recommend 15 minutes a day in the sun without sunscreen. It’s not long enough to burn your skin, but it is long enough to substantially improve your health.
So the next time you feel like relaxing in the sun, just remember your body is relaxing too—and lowering your blood pressure.
1“UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure independently of nitric oxide synthase.” J Invest Dermatol, 2014 Jul;134(7):1839-46.