Understanding Sleep Cycles
Sleep occurs in 90-minute cycles. Waking up at the end of a cycle prevents sleep inertia and helps you feel more refreshed.
Sleep Optimization Suite
Scientific tools to help you wake up refreshed, manage your sleep debt, and understand your caffeine intake.
Cycle Calculator
Wake up at the end of a 90-minute cycle.
14 min
Wake Up Times
Repaying Sleep Debt
Sleep debt accumulates when you get less rest than your body needs. Consistently adding an extra hour of sleep can help restore cognitive function.
Caffeine & Sleep
Caffeine has a half-life of about 5 hours. Consuming coffee late in the day can block adenosine receptors, preventing deep sleep.
Frequently Asked Questions
How many sleep cycles do I need?
Most adults require 5 complete cycles (7.5 hours). Individual needs vary, but consistency is key.
Why do I feel tired after 8 hours?
You likely woke up in the middle of a deep sleep cycle. Use our calculator to time your alarm better.
Can I catch up on sleep on weekends?
Partially. While you can recover some lost sleep, shifting your schedule drastically on weekends can make Monday mornings harder.
