deep sleep
Far from waking
Deep sleep is the stage of sleep characterized by slow brain waves and minimal responsiveness to external stimuli.
It's the most restorative phase, when the body repairs tissue and consolidates memory.
Someone in deep sleep is difficult to wake: She was in such a deep sleep that she didn't hear the alarm.
Figuratively, deep sleep can mean death or unconsciousness.
Low-frequency brain oscillations
- NREMSleep lacking eye movement
- stage 3Severe disease classification
- stage 4Most severe disease classification
- dreamlessLacking sleep imagery
brain waves · growth hormone · immune function · cognitive function · restorative · unconsciousness · REM cycle · melatonin
Light, restful unconsciousness
- rejuvenationRestoration of youthful vigor
- recoveryRegaining what was lost
- healingRestoration of health
- tranquilityUndisturbed peacefulness
serenity · quietude · repose · peaceful · restorative · refreshed · undisturbed · dead to the world
delta waves
Low-frequency brain oscillations
- NREMSleep lacking eye movement
- stage 3Severe disease classification
- stage 4Most severe disease classification
dreamless · brain waves · growth hormone · immune function · cognitive function · restorative · unconsciousness · REM cycle · melatonin
slumber
Light, restful unconsciousness
- rejuvenationRestoration of youthful vigor
- recoveryRegaining what was lost
- healingRestoration of health
tranquility · serenity · quietude · repose · peaceful · restorative · refreshed · undisturbed · dead to the world · sleeping like a log
- asleepasleep, fast asleep, sound asleep, snoring, sawing logs
- rhyming pairscat hat, true blue, old gold, wild child, sweet treat
- dreamlanddream world, dreamscape, lucid dream, daydream, sweet dreams
- phasesbeta phase, acute phase, design phase, growth stage, life stage
- baby sleepcrib, bassinet, swaddle, swaddling, nap
- biorhythmscircadian rhythm, circadian rhythms, circadian clock, biological clocks, biological clock
deep sleepwakefulness
State of being conscious
wide awake · consciousness · alertness · waking state · hypervigilance