Many kids are tough to get to sleep, and they wake several times during the night. This is not a plot to rob you of your senses; it’s just that children and adults have different sleep patterns, needs, and feelings about sleep.

Why Babies Wake Up So Much

Adult sleep is divided into REM (rapid eye movement) and non-REM sleep. REM sleep is the stage of dreaming. Non-REM sleep is deeper and more refreshing. Adults cycle between the two kinds of sleep every 90 minutes or so, with 20 to 25 percent of their sleep spent in REM periods.

Infants also have REM and non-REM sleep (usually called “active sleep” and “quiet sleep” in babies). But compared to adults, babies spend a greater proportion of their sleep time in REM sleep—anywhere from 50 percent for full-term newborns to 80 percent for premature newborns. In fact, some researchers think that REM sleep may play its most important role before the baby is born, perhaps helping the visual centers of the brain develop in the last two or three months of gestation.

Most important (from many parents’ point of view) is that babies and young children cycle between REM and non-REM sleep more frequently than adults— about every hour. These transitions are the times children are more likely to wake up—to call for you or climb into your bed. By contrast, when children are aroused in the middle of non-REM sleep, they usually just move or whimper and fall back to sleep. So more periods of REM sleep mean more chances for them to wake up in the middle of the night.