小天使（1317)-How Much Sleep Do Children Need?

转自 WebMD Medical Reference

The amount of sleep a child needs varies depending on the individual and certain factors, including the age of the child. Following are some general guidelines:

1-4 Weeks Old: 15 - 16 hours per day

Newborns typically sleep about 15 to 18 hours a day, but only in short periods of two to four hours. Premature babies may sleep longer and colicky ones shorter.

Since newborns do not yet have an internal biological clock, or circadian rhythm, their sleep patterns are not related to the daylight and nighttime cycles. In fact, they tend not to have much of a pattern at all.

1-4 Months Old: 14 - 15 hours per day

By 6 weeks of age your baby is beginning to settle down a bit, and you may notice more regular sleep patterns emerging. The longest periods of sleep run four to six hours and now tends to occur more regularly in the evening. Day-night confusion ends.

4-12 Months Old: 14 - 15 hours per day

While up to 15 hours is ideal, most infants up to 11 months old get only about 12 hours sleep. Establishing healthy sleep habits is a primary goal during this period, as your baby is now much more social, and his sleep patterns are more adult-like.

Babies typically have three naps and drop to two at around 6 months old, at which time (or earlier) they are physically capable of sleeping through the night. Establishing regular naps generally happens at the latter part of this time frame, as his biological rhythms mature. The midmorning nap usually starts at 9 a.m. and lasts about an hour. The early afternoon nap starts from 12 to 2 p.m. and lasts an hour or two. And the late afternoon nap may start from 3 to 5 p.m. and is variable in duration.

1-3 Years Old: 12 - 14 hours per day

As your child moves past the first year toward 18-21 months of age he will lose his morning nap and nap only once a day. While toddlers need up to 14 hours a day of sleep, they typically get only about 10.

Most children from about 21 to 36 months of age still need one nap a day, which may range from one to three and a half hours long. They typically go to bed between 7 and 9 p.m. and wake up between 6 and 8 a.m.

3-6 Years Old: 10 - 12 hours per day

Children at this age typically go to bed between 7 and 9 p.m. and wake up around 6 and 8 a.m., just as they did when they were younger. At 3, most children are still napping while at 5, most are not. Naps gradually become shorter as well. New sleep problems do not usually develop after 3 years of age.

7-12 Years Old: 10 - 11 hours per day

At these ages, with social, school, and family activities, bedtimes gradually become later and later, with most 12-years-olds going to bed at about 9 p.m. There is still a wide range of bedtimes, from 7:30 to 10 p.m., as well as total sleep times, from 9 to 12 hours, although the average is only about 9 hours.

12-18 Years Old: 8 - 9 hours per day

Sleep needs remain just as vital to health and well-being for teenagers as when they were younger. It turns out that many teenagers actually may need more sleep than in previous years. Now, however, social pressures conspire against getting the proper amount and quality of sleep.