The Science of Sleep Phases: Why '8 Hours' Isn't Enough
Quality over quantity. Learn about REM, Deep, and Light sleep cycles and how to optimize your night for physical and mental recovery.
Understanding the Architecture of Sleep
Sleep isn't a monolith. It's a complex cycle that repeats every 90 minutes. Getting "8 hours" means nothing if those hours are fragmented or lack deep sleep.
The 90-Minute Cycle
NREM1 (Drifting)
5-10 MinutesThe bridge between wake and sleep. Muscle relax, brainwaves slow to Alpha/Theta. "Hypnic jerks" happen here.
NREM2 (Light Sleep)
20-25 MinutesBody temp drops, heart rate slows. You spend ~50% of the night here.
NREM3 (Deep Sleep)
20-40 MinutesThe Holy Grail. Physical repair, immune recharge, growth hormone release. SleepHack targets this phase.
REM Sleep
10-60 MinutesDreaming stage. Brain activity spikes. Essential for emotional regulation and memory.
How to Optimize Your Cycles
- Consistency: Go to bed at the same time to train your circadian rhythm.
- Temperature: Keep your room cool (around 65°F / 18°C).
- Sound Environment: Use adaptive audio like SleepHack to prevent noise waking you up and to encourage the brain to stay in NREM3 longer.
Sleep Better Tonight.
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