Why does morning daylight help you sleep at night?
Short answer
Light reaching your eyes is the main signal that keeps your body clock in step with the day. Getting outside soon after waking helps you feel alert earlier and sleepy earlier in the evening.
Key points
- Outdoor light is far brighter than indoor light, even on a cloudy day.
- Light in the morning and darkness in the evening both help.
- Bright light late in the evening works against you.
How it works
Your internal clock is kept in time with the 24-hour day through a pathway from the eyes. Morning light pulls your clock earlier, so sleepiness arrives earlier at night. Artificial light in the evening, which is a recent change in how people live, pushes it the other way.
Making it practical
A walk to the bus, coffee by an open window, or the first part of a commute on foot all count. On dark winter mornings, get outside as soon as it is light, and keep evening light dim.
In your plan
If you can get outdoor light in the morning, your plan builds it into the first part of your day. If you cannot, it relies more on a steady wake time and a dim evening.
Related questions
Why does a fixed wake time matter most?
Because your body clock is set mainly by when you wake and see light. Getting up at the same time every day, weekends included, is one of the most reliable ways to make falling asleep at night easier.
Read the full answerWhat is a wind-down routine?
A wind-down is the same short sequence of calm, low-light activities before bed every night, so your body learns that sleep comes next.
Read the full answerHow late is too late for caffeine?
For many people, caffeine within about six hours of bedtime disrupts sleep, even if they fall asleep easily. A common starting point is no coffee, tea, energy drinks or pre-workout after early afternoon.
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