Circadian Rhythm Alignment
Your circadian rhythm is the roughly 24-hour internal clock that governs when you feel alert, hungry and sleepy. When it is aligned with your actual day, life feels easier. When it drifts, everything from sleep to mood suffers.
What sets the clock
Light is the master signal. Bright light in the morning advances the clock and wakes you up; light at night delays it and pushes sleep later. Meal timing, movement and temperature act as secondary cues. Learn how to use the strongest lever in the impact of morning light.
Signs of misalignment
- Wide awake at night, groggy in the morning.
- Energy crashes at odd times of day.
- Poor sleep despite enough hours in bed.
- Low mood that tracks with dark seasons or shift work.
Daily habits that keep you aligned
Get daylight soon after waking, keep consistent sleep and wake times, eat earlier rather than late at night, and dim lights in the evening. If your rhythm has drifted badly, see how to reset your circadian clock. For the underlying science, the Sleep Foundation's circadian rhythm guide is clear and well-referenced.