Morning sunlight exposure helps set up the circadian rhythm and supports better melatonin production throughout the day, leading to better sleep at night.

“your nighttime routine almost starts in the morning because you're getting morning sunlight in the morning and that sets up your circadian rhythm. Your production of melatonin is something that's engaged with your circadian clock for the whole day. So, I'm going to sleep better at night when I get out first thing in the morning into the sunlight.”