Essentials: Sleep Toolkit for Optimizing Sleep & Sleep-Wake Timing

Morning Cortisol and Sunlight Viewing00:00

Regardless of when you wake up in the morning, body temperature naturally increases, which triggers the release of cortisol. Cortisol should reach its peak early in the day, right about the time of waking. To ensure this peak occurs early, view bright light, ideally from sunlight, within the first 30 to 60 minutes after waking.

There are neurons in the eye called intrinsically photosensitive melanopsin cells that respond best to bright light early in the day. These cells signal to the suprachiasmatic nucleus, a cluster of neurons over the roof of the mouth that sends electrical and chemical signals throughout the body, triggering the cortisol increase, providing a wake-up signal, and setting a timer for sleep later that night.

Practical Morning Sunlight Protocol02:00

Instead of reaching for a phone, get out of bed and go outside. On bright clear days with low solar angle, or on cloudy days, get outside to receive as much light energy or photons in the eyes as possible. Do not stare directly into the sun. Never look at any light that is painful to view. For morning sunlight viewing, do not wear sunglasses. It is fine to wear eyeglasses or contact lenses, as these focus light onto the neural retina and melanopsin cells.

Hundreds to thousands of peer-reviewed papers show that light viewing early in the day is the most powerful stimulus for wakefulness throughout the day and has a powerful positive impact on the ability to fall and stay asleep at night.