The sleep of an infant is quite unlike that of an adult. Not only do babies spend more time sleeping than adults, they also have different sleep patterns. Knowledge of how babies sleep helps with understanding why they need to sleep as much as they do.

Why Baby’s Sleep is Different

Basic biology plays a big part in the reasons a baby’s sleep requirements differ from those of adults. Circadian rhythms, those natural signals that tell us when to eat and sleep, do not develop in babies until they are 4 to 6 months old. As a result, babies can become hungry or tired at any time, not on any set schedule, like adults.

In both infants and adults, sleep is divided into active and quiet stages. Active sleep is also known as rapid eye movement or REM sleep. Dreaming occurs during this stage. Quiet sleep (also called non-REM sleep) consists of four phases: drowsiness, light sleep, deep sleep and very deep sleep.

Newborn sleep patterns start with a brief REM stage, progress through the four stages of quiet sleep, and move into REM sleep to begin the whole cycle again. Adults begin with stage 1 of quiet sleep, go through the other three stages and have some REM sleep, but not nearly as much as babies.

REM sleep is very important, especially for infants. Research suggests that REM sleep assists with brain development, even before a baby is born: REM sleep has been credited with providing visual imagery that helps the mental development of the fetus. This theory is supported by further research that indicates that as we age, we require less REM sleep. Fetuses have about 100% REM sleep, two-year-olds 25%, adults 20% and the elderly about 15%. In other words, the body provides babies with more REM sleep because it is needed for their rapid brain development. As brain development slows, the amount of REM sleep decreases, diminishing almost to adult levels by the toddler years.

How Much Sleep is Enough?

Nighttime sleep and daytime naps are both important factors in the sleep equation for babies. The following table outlines the total amount of sleep a child needs at various ages, as well as how much of that sleep should come from naps. Keep in mind that the numbers here are guidelines: babies can and do vary from these norms.

Parents of newborns will find that their babies sleep in shorter blocks of time throughout the day and night. Newborns, adjusting to a whole new world, tire easily and sleep whenever they need to. Most newborns sleep about 18 hours a day, in 2 to 4 hour naps.

The Importance of Naps

Parents whose babies sleep less than the norm at night might be tempted to skip or shorten a nap in the hopes that Baby will turn in earlier and sleep longer. Sounds like a good plan, doesn’t it? Unfortunately, you’ll find that this theory doesn’t work so well when applied to the real world, where naps are just as important as night sleeping for infants and toddlers. In fact, a child who needs a nap but does not get one can become overtired and have trouble falling asleep at night. Even if your child does not nap as long as what the experts tell you, you should still make sure that at least some of your child’s daily sleep quota comes in the daytime hours.