Viewing sunlight around sunset can adjust the eyes' sensitivity to artificial lights later at night without disrupting the circadian clock.

“Late afternoon sunlight viewing partially offsets artificial-light-induced-suppression of melatonin at night.”

“This has to do with altering retinal sensitivity in a circadian dependent way.”

“Turns out, viewing sunlight in the late afternoon or evening *partially* offsets the negative impact of artificial light at night.”

“It reduces the sensitivity of your circadian visual system, so you can tolerate more artificial light at night w/o messing up your sleep.”

“Getting some sunlight in your eyes in the late afternoon or evening partially offsets the negative effects of artificial light at night on (reducing) your melatonin levels and sleep.”

“the longer you've been awake, the more sensitive your retina and these cells are to light, so that if you've been awake for 10, 12, 14 hours, it becomes very easy for even a small amount of light coming from a screen or from an overhead light to trigger the activation of the clock and make you feel like you wanna stay up later, make it harder to fall asleep, and disrupt your sleep pattern, okay?”

“Then I've recommended, based on scientific literature, that you look at sunlight sometime around the time when the sun is setting and the reason for that of course is because it adjusts down the sensitivity of your eyes because here's the diabolical thing.”

“If you see afternoon light, you're going to adjust down the sensitivity of your eyes so that you have a little bit more wiggle room, a little bit more leeway to view lights from screens and overhead lights even late at night without disrupting your circadian clock.”

“Think about the afternoon sunlight viewing as kind of a, I think of it as kind of a Netflix inoculation.”

“if you get outside and see the sun as it arcs down, or if you can't see the sun directly, get some sunlight in your eyes in the afternoon hours, so maybe 4:00 PMish, and do that for 20, 30 minutes, maybe reading outside or taking a walk, I walk the dog again, that's my protocol, in order to get that evening light, what it does is it lowers the sensitivity of your retina in the late evening hours, which allows you to buffer yourself against the negative effects of bright light later at night.”

“So get that afternoon light. So what you'll probably notice is that the optimal protocols for optimizing your brain and body health and performance and sleep, et cetera, are actually really simple. But just because they're simple does not mean that they are not powerful; in fact, they are very powerful because they leverage the most powerful technology that exists, which is your nervous system.”

“well, doing that is going to slightly, but not completely, offset any of the negative effects of viewing artificial light at night.”

“Viewing, so sunlight to the eyes, sunlight in the late afternoon and evening hours... doing that in the afternoon serves an additional beneficial purpose, which is you protect or you inoculate your nervous system against some of the negative effects of bright artificial light or even dim artificial light in the nighttime hours between 10:00 p.m. and 4:00 a.m.”

“And then in the evening, by getting sunlight in your eyes again, in particular, sunlight that comes from low solar angle sunlight, well, that provides a second stimulus or a second reference point that tells your brain and body, "Hey, it's evening. The sun is descending."”

“we know based on a really nice study publish in science reports that if you view that afternoon late afternoon evening sunlight you don't have to be too strict about the time get you know pop your sunglasses off as long as you can do that safely get some sunlight in your eyes or if you can't look directly at the Sun and by the way never stare directly at the Sun at least getting some daylight in your eyes before the sun goes down that can offset that melatonin reduction by about 50 %”

“getting some sunlight in your eyes before the sun goes down maybe for 5 10 minutes it's not as important as the morning sunlight but it does have a great benefit and the benefit is it adjusts the sensitivity of the neurons in your retina and in your brain such that it protects you against brighter artificial lights later in the evening”

“There was a really nice study that showed that viewing sunlight around the time of sunset doesn't have to be just crossing the horizon, but circa sunset within an hour or so of sunset prevents some of the bad effects of light in preventing melatonin release later that same night.”

“What it does is it lowers the sensitivity of your retina in the late evening hours, which allows you to buffer yourself against the negative effects of bright light later at night.”

“Viewing that sunlight will actually adjust the sensitivity of your retina a little bit such that bright light from artificial sources won't have quite as much of a detrimental effect at suppressing melatonin at night when you're indoors under artificial lights.”