Ideal Range
1.5-2 hours (20-25% of total sleep) for adults
Related Metrics
What is REM Sleep?
REM sleep is characterized by rapid eye movements, vivid dreams, and temporary muscle paralysis. This stage is critical for memory consolidation, emotional processing, and cognitive restoration.
Why REM Sleep Matters
REM sleep is your brain's maintenance mode. It consolidates memories, processes emotional experiences, and enables creative problem-solving. Inadequate REM impairs learning, emotional regulation, and next-day cognitive performance.
How to Improve REM Sleep
Common Mistakes
- Caffeine too late in the day stealing REM
- Alcohol before bed - the REM-killer
- Cutting sleep short (most REM is in final cycles)
- Using sleep aids that suppress REM architecture
- Chronic stress keeping cortisol elevated
The Science
REM sleep cycles get longer as the night progresses. Your first REM period might be 10 minutes, while the last could be 60+ minutes. During REM, your brain is highly active - similar to wakefulness - while your body is paralyzed (atonia) to prevent acting out dreams. The prefrontal cortex is less active, allowing unconstrained associations that enable creativity and emotional processing.
Other Sleep Metrics
Deep Sleep
Deep sleep, also called slow-wave sleep (SWS) or N3 sleep, is the most restorati...
Ideal: 1.5-2 hours (15-25% of total sleep) for
HRV
Heart Rate Variability measures the variation in time between heartbeats. Higher...
Ideal: Highly individual - track your personal
Sleep Efficiency
Sleep efficiency is the percentage of time in bed that you actually spend sleepi...
Ideal: 85-95% for healthy adults. Above 95% mig
Sleep Latency
Sleep latency is the time it takes you to fall asleep after getting into bed and...
Ideal: 10-20 minutes is ideal. Falling asleep i