Light and your body clock
How light sets your sleep, morning to night.
Light is the main cue for your body clock. Handling it well, morning to night, helps your body know when to sleep.
Your body clock
- Your body runs on a roughly 24-hour clock. Light is what resets it every day.
- In the evening, in darkness, your body makes melatonin, the hormone that gets you ready for sleep.
Morning light
- A good dose of light in the morning, ideally outside, sets your clock and supports alertness.
Screens in the evening
- Screen light, rich in blue, can hold back melatonin and delay falling asleep.
- Dim the lights and put screens down in the evening to let night settle in.
Frequently asked questions
How does light act on sleep?
Light is the main cue for your body clock, which runs on a roughly 24-hour cycle. In the evening, in darkness, your body makes melatonin, the hormone that prepares for sleep.
Why get light in the morning?
A good dose of light in the morning, ideally outdoors, sets your body clock and supports alertness through the day.
Does screen light keep you from sleeping?
Screen light, rich in blue, can curb melatonin and delay falling asleep. Dim the lights and put screens away in the evening to let night settle in.