A sleep cycle lasts about 90 minutes and includes all stages of sleep: N1 (light), N2 (true sleep), N3 (deep sleep), and REM sleep. Completing full cycles helps you wake up feeling refreshed.
How many sleep cycles do I need?
Most adults need 5-6 complete sleep cycles per night, which equals 7.5-9 hours of sleep. The exact amount varies by individual and age.
Why do I wake up tired?
Waking up in the middle of a sleep cycle (especially deep sleep) can cause sleep inertia. Try to wake up at the end of a cycle when you're in lighter sleep.
What is REM sleep?
REM (Rapid Eye Movement) sleep is when most dreaming occurs. It's crucial for memory consolidation, learning, and mood regulation. Adults typically get 1.5-2 hours of REM sleep per night.
How can I improve sleep quality?
Maintain consistent sleep schedule, create a dark and cool sleep environment, limit caffeine and screen time before bed, and manage stress through relaxation techniques.