Why is morning sunlight important?

Morning sunlight helps set your circadian clock, promoting alertness during the day and making it easier to fall asleep at night. 1

• Cortisol and alertness: Morning light helps time the early-day cortisol rise, which supports immune function and boosts focus, alertness, and the ability to move. 2
• Sleep timing: The light signal starts a timer for sleep later that night; morning light also helps keep cortisol and other activating signals high earlier and low at night, when melatonin supports sleep. 3 4
• Mood and broader benefits: Regular morning daylight supports mood, focus, alertness, and nighttime sleep; the same light-sensitive circadian pathways are present in children and dogs and other animals. 5 6
• When and how: Get outside soon after waking when possible. If you wake before sunrise or cannot get natural light, a bright light designed to simulate sunlight can help, though sunlight is preferable. 7 8
• Eye safety: Do not stare at the sun or force yourself to look at light that feels painful; blink and look slightly away if needed. 9