Ideal Range
1.5-2 hours (15-25% of total sleep) for adults
Related Metrics
What is Deep Sleep?
Deep sleep, also called slow-wave sleep (SWS) or N3 sleep, is the most restorative sleep stage. During this phase, your brain waves slow to delta waves, growth hormone is released, and physical restoration occurs.
Why Deep Sleep Matters
Deep sleep is when your body physically repairs itself. Human Growth Hormone (HGH) floods your system, muscles repair, tissues regenerate, and your immune system rebuilds. Without adequate deep sleep, athletic recovery suffers, injury risk increases, and aging accelerates.
How to Improve Deep Sleep
Common Mistakes
- Drinking alcohol thinking it helps sleep (it destroys deep sleep)
- Exercising too close to bedtime
- Sleeping in a room that's too warm
- Inconsistent sleep schedule fragmenting sleep architecture
- Eating large meals close to bedtime
The Science
Deep sleep occurs predominantly in the first half of the night. Your brain produces slow delta waves (0.5-4 Hz), and your body enters its most anabolic state. Growth hormone secretion peaks during the first deep sleep cycle. This is also when the glymphatic system clears metabolic waste from the brain, including amyloid-beta proteins associated with Alzheimer's.
Other Sleep Metrics
REM Sleep
REM sleep is characterized by rapid eye movements, vivid dreams, and temporary m...
Ideal: 1.5-2 hours (20-25% 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