TUESDAY, Nov. 27 (HealthDay News) -- Despite concerns to the contrary, American children do seem to be getting adequate sleep, a new analysis reveals.

"Our estimates are in line with the amount of sleep recommended for children by the [U.S.] Centers for Disease Control and Prevention, which suggests that children in the U.S. are getting an appropriate amount of sleep on average," said study author Jessica Williams, a doctoral candidate at the Fielding School of Public Health at the University of California, Los Angeles.

The finding stems from an in-depth look at current sleep norms among infants and children, as reflected by data collected in 1997 -- with follow-ups in 2002 and 2007 -- by a large National Science Foundation survey that set out to assess behavioral and mental health development from birth through age 18.

Williams and her colleagues report their findings in the Nov. 26 online issue of the Archives of Pediatrics & Adolescent Medicine.

The authors noted that the CDC recommends that children between the ages of 1 and 3 years get roughly 12 to 14 hours of sleep per day, while those between ages 3 and 5 years should get 11 to 13 hours per day. By the time kids reach the ages of 5 to 10 years, 10 to 11 hours of sleep are deemed sufficient. By adolescence, 8.5 to 9.5 hours of sleep is considered enough.

In the survey, childhood activities, including sleep time, were detailed in family diaries logged by survey participants, which initially included about 2,800 children, later dropping to about 1,400 children by the final follow-up.

The investigators determined that infants were sleeping an average of 13-plus hours per day, a figure that slowly but continuously fell as they aged through adolescence. By the time teens were between 14 and 18 years old, the average amount of sleep hovered at about nine hours per day, with all the figures holding up regardless of race or ethnicity.

Daytime sleep was much higher among infants, with a fall-off by the time children reached school age. The team further observed that older children tended to sleep more during the weekend than during the week.

The researchers concluded that American children do seem to be getting the recommended amount of age-appropriate sleep, contrary to what they suggested was mostly unsubstantiated anecdotal evidence that recent generations of infants, preteens and teens have been struggling with mounting sleep deprivation.

That said, Williams cautioned that while her analysis shed some light on the normal patterns of sleep among American children -- and how closely they matched current recommendations -- it did not render any verdict as to whether or not such patterns are, in fact, healthy.

But Williams nonetheless suggested that the norms observed in the study might "be used by clinicians and parents to determine when a child falls far from the median as a signal that that child's sleep patterns may need further assessment."

For her part, Shelby Freedman Harris, director of the behavioral sleep medicine program and of the Sleep-Wake Disorders Center at Montefiore Medical Center in New York City, said that "this study stands out because it suggests something very different than previous reports of sleep averages in kids."

She noted: "Many papers have found that kids are getting less sleep on average than this paper did. Others suggest different sleep averages based on racial/socioeconomic differences, and these researchers didn't. The averages that each age group [were] getting in this study was on par with the current sleep-need guidelines in the sleep field."

However, added Freedman Harris, who is also an assistant professor of neurology and psychiatry at the Albert Einstein College of Medicine, "What is not surprising though, but consistent with pediatric sleep knowledge, is the gradual decrease of sleep-need as kids get older. Sleep helps kids' bodies grow at a rapid rate. It helps their brains develop. As they get older and drop naps, their total sleep times gradually decrease. In adolescence, it is thought that teens' melatonin levels drop off and delay, leading to later bed [times]."

Melatonin is a hormone that helps regulate the body's sleep-wake cycles.

Freedman Harris also stressed that the amounts of sleep found in the study aren't necessarily the ideal for kids' health. "It does help to guide treatment recommendations though, if a child is significantly higher or lower, sleep-wise, than the average," she said.

More information

For more on sleep, visit the U.S. Centers for Disease Control and Prevention.