UV in sunlight hits the skin, releases NO, which moves into circulation, which dilates arteries, which lowers blood pressure, so you don't get a heart attack or stroke, and you live longer. Dermatologists don't care

Professor Richard Weller: "We then shone UV at the arm. And we either shone UV at the arm so rays hit it, or we shone UV at the arm but it was covered with a foil blanket so the temperature rises but UV doesn't hit the skin. And what we showed was that when you irradiate the forearm it causes vasodilation. So ultraviolet in man is an arterial vasodilator, and the sham arm there was no vasodilation. So UV in man is a direct vasodilator.

"Blood pressure is a function of total peripheral resistance and cardiac output. So you multiply what the heart cardiac output is by the peripheral resistance (and the more constricted vessels are the greater the resistance), and the function of those two gives you blood pressure. So we then stood people in UV cabinets or we lay people under full-length UV lamps, and we showed that shining UV at people lowers blood pressure. The sham irradiation, covered with the foil blanket so that the temperature goes up and not the rays, there's a fall in blood pressure while the lamps are on because you get warm. But as soon as the lamps are off, the sham irradiation returns to normal, but the actively irradiated stays down.

"And then you have a rise in circulating nitric oxide in the irradiated group and a fall in nitrate. So sunlight hits the skin, releases NO, which moves into the circulation, which dilates arteries, which lowers blood pressure, so you don't get a heart attack or stroke, and you live longer. That's great.

"So that was super. Of absolutely zero interest to dermatologists. Not interested at all. Couldn't be. They really don't care."

Professor Richard Weller @ 32:01–34:06 (posted 2025-10-11) https://youtu.be/uqVLQdC4qoc&t=1921