- REM sleep
- Stage 1-3 NREM sleep (previously stage 1-4)
A night of sleep comprises 4 to 6 cycles through sleep stages and each cycle is around 90 minutes.
TODO: hypnograms
REM Sleep
Rapid eye movement sleep (REM) Dreaming usually occurs during REM Muscles paralysed Time in REM sleep increases through the night (25% of total sleep time)
NREM Stages
- stage 1: Transition between wake and sleep. Easy to wake from, may not be aware asleep (5% of total sleep time)
- stage 2: Light sleep (45%)
- stage 3 - previously devided into stage 3 and 4: also known as slow-wave sleep (SWS), deep sleep, harder to wake from. Results in “sleep inertia” if woken from this stage (25%)