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Basics

Your body keeps daily time

Connect light cues with the timing of a daily rhythm.

A clock is divided into day and night colors, with sun and moon symbols. Light cues point toward a body clock, linking environmental timing with a daily sleep-wake rhythm. — View full screen Download the infographic

The picture in words

Light cues: Light and darkness provide timing information.
Body clock: The central clock helps coordinate daily rhythms.
Daily timing: Individual sleep-wake timing can differ.

Reading the illustration

Follow the connections from the environment to the clock and daily timing. The diagram shows a relationship, rather than a prescribed bedtime.

Try a question

How can changing light exposure matter for daily timing?

Show the explanation

Light reaching the eyes provides a cue that helps align the body clock with the environment.

Read the sources

National Heart, Lung, and Blood Institute. (2022b, March 24). How sleep works: Your sleep/wake cycle. https://www.nhlbi.nih.gov/health/sleep/sleep-wake-cycleSelected rendered passages: environmental cues and the biological need for sleep.

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