Sleep Health Article

Sleep

The natural, periodic suspension of consciousness needed to revive the body.

There is no one acceptable pattern of sleep for all children. As a child develops from infancy through childhood and adolescence, sleep patterns change. In addition, there are also differences between the sleep needs of children at the same stage of development; some children naturally sleep for a shorter period of time, while others need a greater than average amount of sleep. The vast majority of children get enough sleep to meet their needs. As long as a child's sleep pattern is consistent, and she does not exhibit signs of excessive sleepiness or fatigue during the daytime, the quantity and quality of her sleep are probably adequate.

Infancy

Newborn infants sleep in short periods throughout the day and night, totaling up to 18 hours out of every 24. Like all human sleep, the sleep of young infants is divided into two types, non-REM sleep, which gradually progresses through four stages of increasingly deep sleep, and REM (rapid eye movement) sleep, the lighter sleep during which dreaming occurs. About half of a newborn's sleep time is spent in REM sleep. These are the periods when infants are most likely to squirm, yawn, or make soft noises in their sleep, and also the times when they are most easily awakened. As children grow older, their need for REM sleep declines, and it accounts for an increasingly smaller percentage of their nightly sleep time. For example, a toddler spends only about 30% of his sleep time in REM sleep, in contrast to the newborn's 50%. Corresponding to this gradual reduction in REM sleep, dreaming decreases dramatically as children get older. Infants spend about 40% of their sleep time dreaming, as opposed to 20% for adults. Infants have a cycle of REM and non-REM sleep that typically lasts 90 minutes, and they rise to a near-waking state every three to four hours. This cycle sets the pattern for night-time feedings, which typically occur at about 2:00 and 6:00 AM. Later, babies become able to comfort themselves during these near-awakenings, and their sleep cycles gradually become longer until they eventually sleep through the night.

By the age of two months, an infant's sleep has concentrated itself into a less diffuse schedule of regular naps. By three months, 70% of babies are able to get most of their sleep in one nighttime stretch, going through several consecutive cycles of REM and non-REM sleep. This number rises to 83% by the age of six months and 90% by one year. By four months of age, most infants can sleep through a 12-hour stretch with only one awakening. In the first months of life, environmental Stressors and emotional issues do not intrude on an infant's sleep, and babies basically go to sleep whenever they are sleepy, unless they are hungry or in pain. By the end of the first year, however, external factors such as excitement or anxiety can keep a child from falling asleep naturally. During this time, she is learning the new skills of sitting, crawling, and walking, and the daytime excitement of mastering these activities can spill over into the night, creating a temporary regression in sleep patterns.

Toddlerhood and preschool age

By the age of one year, there can also be active resistance to going to bed, either because of reluctance to give up the stimulation and fun of being awake or because of fears and anxieties. Bedtime may trigger separation anxiety—the fear that while the child is asleep, he will lose or be abandoned by his parents—or other nighttime fears, such as fear of the dark or fantasies about monsters under the bed or in the closet. Between the ages of one and three years, children develop various strategies for resisting being put to bed—asking for another kiss, another story, a glass of water, or anything else they think will delay the final goodnight. They may also want to sleep in the parents' bed. For these children, it is helpful to get them to wind down, both mentally and physically, so they are ready for sleep. Comforting, enjoyable bedtime routines, such as a snack, a warm bath, a bedtime story, or a ritual of saying goodnight to the child's toys, can help a child calm down from the day's activities and mentally prepare for nighttime separation from parents.

Sleep problems caused by separation anxiety usually peak in the second and third year and end by the fourth. The worst of a child's resistance to bedtime is usually over by about the age of three years. Sometime after the age of three, bedtime can also be made more attractive by the replacement of the child's crib with a youth- or adultsized bed and the creation of an appealing bedroom environment. During this period, the primary disruption of a child's sleep usually comes from nightmares, which are most prevalent between the ages of three and five, occurring as often as once or twice a week. Even though they can be upsetting, nightmares, especially at these ages, when the child's vivid daytime fantasy life is carried over into sleep, are not a cause for concern unless a child has the same nightmare repeatedly within a short period of time. Another form of sleep disturbance sometimes confused with nightmares is night terror, which is most common in children between the ages of six months to four years and is characterized by screaming, thrashing, sweating, rapid breathing, and confusion. Night terrors usually occur early in the night, often about two hours after a child falls asleep. Unlike nightmares, which are dreams and occur during REM sleep, night terrors occur during deep, non-REM sleep and are thought to be caused by a central nervous system response to momentary physical pain or discomfort, as opposed to nightmares, which are psychological in origin. Night terrors are most closely related to parasomnias, conditions such as sleepwalking in which normal daytime activities are performed during sleep. After the age of five, enuresis or bedwetting, is also classified as a parasomnia. These conditions, which are most common in early and middle childhood, are usually outgrown, with the exception of tooth grinding, which may persist into adulthood. During the preschool years, daytime napping decreases, and most children give up the daytime nap by the age of four or five, making do with about 11 hours of sleep at night.