Ten to fifteen minutes of light exposure is sufficient to set the circadian clock, with longer durations recommended if it is darker.

“To set your circadian rhythm for improved daytime mood & alertness & deeper sleep, get outside sans sunglasses in the morning for 20-30min (if overcast), 5-10min (if clear out).”

“10min of viewing sunlight each morning, 20 on cloudy days to wake up & sleep better”

“get up each morning, try and get outside, I know that can be challenging for people, but anywhere from 2 to 10 minutes of sunlight exposure is going to work well for most people, and you wanna do this on a regular basis”

“10 to 15 should be sufficient. Stay for half an hour. Stay for 45 minutes. If it's very darker out, stay for longer.”

“On a day where there's cloud cover, so the sun is just peeking through the clouds or it's more dense cloud cover, you want to get about 10 minutes of sunlight exposure to your eyes early in the day. And on days that are really densely overcast or maybe even are rainy, you're going to want to get as much as 20 or 30 minutes of sunlight exposure.”

“And get that morning sunlight to set your circadian rhythm, because of course, your circadian rhythm is what anchors it all.”

“I turn on this light which is specifically emulate the light you get from the Sun it helps me feel awake in that moment it helps me also feel more alert during the day it cements my circadian rhythm which improves the sleep of the night there's a lot of research that shows that this is very helpful”

“I try to get as much sunlight in my eyes first thing in the morning when I wake up and this is not with contacts or sunglasses which I think can impair your eyes and your suprachiasmatic nucleus in your brain the ability of your body to tell what time of day it is”