What is the optimum amount of sleep for kids?

By Dr. Ananya Mandal, MDFeb 14 2012

New research shows that children are getting less sleep than they need. According to an article published online Monday by the journal Pediatrics, 32 sets of sleep guidelines for kids – containing 360 distinct recommendations for children of specific ages – were published between 1897 and 2009. During that time, the amount of recommended sleep fell by an average of 0.71 minutes per year. That added up to about 70 fewer minutes of suggested nightly sleep over the course of the 20th century.

The article suggests that of the 360 sleep recommendations made over the years, researchers at the University of South Australia's Health and Use of Time Group, have found data that corresponded to 173 of them. In 83% of the cases, children were falling short of the ideal – and doing so by an average of 37 minutes. Overall, the actual amount of nightly sleep for children fell by an average of 0.73 minutes per year.

“There is almost no empirical evidence for the optimal sleep duration for children,” the authors write. “Sleeping longer does not indicate a need for more sleep,” the authors wrote, “in the same way that eating more does not indicate a need for more food.”

A systematic review of the literature revealed that, sleep recommendations for children of all ages have consistently exceeded what was known about actual sleep time, according to Lisa Anne Matricciani and colleagues at the University of South Australia in Adelaide.

Only one case was noted for which the expert guidelines were rooted in medical evidence of a need for a particular amount of sleep. That was a 1926 study that measured the actual sleep of 500 kids between the ages of 6 and 15 who were deemed “healthy.” Other than that, it seems that experts simply looked at the amount of sleep children around them were getting and figured that they really needed a little bit more, the authors wrote.

“The hurry and excitement of modern life is quite correctly held to be responsible for much of the insomnia of which we hear,” according to an editorial published in the British Medical Journal way back in 1894. As the Australian researchers explain, “In the early 1900s, artificial lighting, radio, reading, and the cinema were considered to be the causes of delayed bedtimes. By the late 1990s, video games, television viewing, the Internet, and mobile telephones were largely held responsible for such delays.”

A limitation of the study was that in this review, sleep duration was based on reports, rather than on objective measures such as actigraphy and polysomnography. But those approaches have only been developed recently, are expensive and time-consuming, and have usually been applied only at the individual level, the authors noted.