Sleep Cycle Calculator

The Science of Sleep Cycles

Sleep isn't a uniform state — your brain cycles through distinct stages approximately every 90 minutes. Each cycle includes light sleep (stages 1-2), deep sleep (stage 3), and REM sleep. Waking up at the end of a complete cycle, during light sleep, helps you feel alert and refreshed rather than groggy.

Tips for Better Sleep

1. Keep a consistent schedule: Go to bed and wake up at the same time every day, even weekends.
2. Create a dark, cool room: Ideal sleep temperature is 60-67°F (15-19°C).
3. Avoid screens before bed: Blue light suppresses melatonin production. Stop screens 1 hour before bed.
4. Limit caffeine after noon: Caffeine has a half-life of 5-6 hours and can disrupt deep sleep.
5. Exercise regularly: But finish vigorous exercise at least 3 hours before bedtime.