STAGES OF SLEEP DURING THE NIGHT

There are two different kinds of sleep: REM and non-REM sleep states:

REM (Rapid Eye Movement)

This is the light state in which dreams occur.  Babies spend about 16 hours each day sleeping and half of this is in REM sleep.  Older children and adults not only sleep for fewer hours but spend much less time in REM sleep.

Non-REM sleep

Non-REM sleep has four different stages:

Stage 1: Drowsiness – baby’s eyes may droop, may open and close slowly, baby may doze.

Stage 2: Light sleep – baby may startle or jump with noise

Stage 3: Deep Sleep – baby is quiet and still

Stage 4: Very deep sleep – baby is still and does not make any noise

With this visual you can see a baby’s sleep has much lighter sleep after midnight which will contribute to waking up if they cannot get themselves back to sleep on their own.  A baby will still wake up during the night even after they have learned to fall to sleep unassisted, they just will not need your help to get back to sleep.