Find the best times to fall asleep or wake up to complete full sleep cycles.
6 cycles (9 hrs) — Best—
5 cycles (7.5 hrs) — Great—
4 cycles (6 hrs) — OK—
3 cycles (4.5 hrs) — Minimum—
Each sleep cycle ≈ 90 minutes
Waking between cycles (not during REM) helps you feel refreshed.
Adults need 5-6 cycles (7.5-9 hours) per night.
How Sleep Cycles Work
Each night you cycle through light sleep, deep sleep, and REM sleep in approximately 90-minute intervals. Waking at the end of a complete cycle (rather than in the middle of deep or REM sleep) makes you feel more alert and less groggy.