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WebMD: 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.

Is there scientific research that backs those numbers for the need of sleep of children?

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Yes, there does appear to be some scientific experimental evidence to support these hours.

In the longitudinal study of adolescents by Carskadon, time in bed was fixed at 10 hours a night, and the data showed that youngsters across the span of ages 10 to 17 slept about 9 hours and 20 minutes. The younger children were more likely to waken spontaneously in the lab, whereas the older children took a bit longer to fall asleep and were rarely spontaneously awake at the end of the 10 hours.[1]

Even though younger children and adolescents slept the same hours, the latter were less alert across the day

Furthermore, assessment with the multiple sleep latency test (MSLT, an objective measure of sleepiness) showed that the younger children were more alert across the day, whereas the pubertal and postpubertal adolescents showed a midday trough of alertness in spite of the same amount of nocturnal sleep [2]

and the need for sleep only diminishes in late adolescence

In summary, current data on the maturation of the biological regulation of sleep during adolescence show that:

  • the circadian timing system undergoes a phase delay;

  • the dissipation of sleep homeostatic pressure does not change until late adolescence when it shows evidence of slowing;

  • the accumulation of sleep homeostastic pressure slows during puberty.

These findings support the notion that the need for sleep is stable (or increases) acrosse adolescent development and that the delay of sleep timing is supported by the circadian shift as well as the slowing of sleep homeostatic pressure accumulation. [3]


[1] Carskadon MA, Orav EJ, Dement WC. Evolution of sleep and daytime sleepiness in adolescents. In: Guilleminault C, Lugaresi E, editors. Sleep/wake disorders: Natural history, epidemiology, and long-term evolution. Raven Press; New York: 1983. pp. 201–16.

[2] Carskadon MA, Harvey K, Duke P, Anders TF, Litt IF, Dement WC. Pubertal changes in daytime sleepiness. Sleep. 1980;2(4):453-60. PubMed PMID: 7403744.

[3] Carskadon MA. Sleep in adolescents: the perfect storm. Pediatr. Clin. North Am. 2011 Jun;58(3):637-47. doi: 10.1016/j.pcl.2011.03.003. PubMed PMID: 21600346.

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Is there scientific research that backs those numbers for the need of sleep of children?

It is not known. This is the trend:

Total average sleep was estimated at more than 13 hours a day for infants, decreasing steadily throughout childhood and early adolescence, reaching about 9 hours a day for 14- to 18-year-olds. ... These estimates are consistent with the amount of sleep recommended for children, and no evidence was found of racial/ethnic differences [1].

But a comment [2] on this study states that:

... we are still far from understanding what a "normal", "ideal" or "adequate" sleep duration is for an individual child to promote optimal health and functioning.

And there is a general belief that children need more sleep:

A lack of empirical evidence for sleep recommendations was universally acknowledged. Inadequate sleep was seen as a consequence of "modern life," associated with technologies of the time. No matter how much sleep children are getting, it has always been assumed that they need more [3].


References:

  1. Williams JA, Zimmerman FJ, Bell JF. Norms and trends of sleep time among US children and adolescents. JAMA Pediatr. 2013 Jan;167(1):55-60. doi: 10.1001/jamapediatrics.2013.423. PubMed PMID: 23403646.
  2. Jenni OG. How much sleep is "normal" in children and adolescents? JAMA Pediatr. 2013 Jan;167(1):91-2. doi: 10.1001/jamapediatrics.2013.429. PubMed PMID: 23403792.
  3. Matricciani LA, Olds TS, Blunden S, Rigney G, Williams MT. Never enough sleep: a brief history of sleep recommendations for children. Pediatrics. 2012 Mar;129(3):548-56. doi: 10.1542/peds.2011-2039. PubMed PMID: 22331340.

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