How Sleep Cycles Work
Sleep occurs in cycles of approximately 90 minutes, moving through stages: light sleep → deep sleep → REM sleep. Waking up between cycles (rather than in the middle of one) helps you feel more refreshed.
Optimal Sleep = 5 or 6 complete cycles = 7.5 or 9 hours
Tips for Better Sleep
- Keep a consistent sleep schedule — even on weekends
- Avoid screens 30-60 minutes before bed (blue light suppresses melatonin)
- Keep your bedroom cool (65-68°F / 18-20°C)
- Limit caffeine after 2 PM
- Exercise regularly, but not within 3 hours of bedtime
Frequently Asked Questions
Why do I feel tired after 8 hours of sleep? You may be waking in the middle of a sleep cycle. Try sleeping 7.5 or 9 hours instead to complete full cycles.
Is 6 hours of sleep enough? For most adults, no. The CDC recommends 7-9 hours. Consistently sleeping less than 7 hours increases health risks.