Viewing sunlight shortly after waking is the most effective way to anchor the circadian clock and regulate the timing of cortisol and melatonin production.

“it's critically important that you get outside to get this light. I had a discussion with a colleague of mine, Dr. Jamie Zeitzer, who's in the Department of Psychiatry and Behavioral Sciences at Stanford, a world expert in this, and he tells me that it's 50 times less effective to view this sunlight”