Sleep, perchance to learn: schoolchildren need to stay in bed longer
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Over the past 15 years, abundant scientific evidence has accumulated that shows America's schoolchildren are chronically sleep deprived, and it is affecting their learning, mood, safety and health.
Furthermore, the general trend is only worsening, with children of all ages receiving, on average, about one hour per night less sleep than their peers a generation ago. Although many factors have contributed to this decline, one pervasive problem that has received significant attention is early school start times.
The National Sleep Foundation makes the following recommendations: School-age children (5 to 10 years) should get 10 to 11 hours of sleep per night; "teens" (10 to 17 years) should get 8.5 to 9.25 hours of sleep per night.
In stark contrast to these recommendations, a 2005 NSF telephone survey of teenagers and their parents showed only 60 percent of ninth-graders got at least eight hours of sleep per night. By the 10th grade, the number had dropped to 30 percent, and it continued to fall. By 12th grade, only 9 percent were getting an optimal amount of sleep as defined by the NSF guidelines.
In 2007, the Centers for Disease Control and Prevention's Youth Risk Behavior Survey, involving 12,154 students nationwide, confirmed those findings reporting that 69 percent of students had insufficient sleep on school nights, with only 7.6 percent reporting optimal hours of sleep. These objective measures are reinforced by the students' self-reports that more than 50 percent feel they don't get enough sleep to "perform at their best."
Still not convinced? Ask any parent of a teen when their adolescent awakens on the weekends and holidays, when they are not constrained by early school start times.
While children of all ages can be affected by inadequate sleep, the situation with older teens is especially acute. As we have seen, student sleep time progressively declines over the high school years as social, athletic and academic demands increase.
This situation is compounded by biological changes in the sleep pattern of adolescents. When it starts to get dark, preadolescents and adults begin to secrete a hormone, melatonin, which makes us sleepy. During puberty, there is a "phase shift" in the circadian rhythm system, our so-called biological clock, which results in the release of melatonin being delayed as much as two hours. It is this phase shift, at least in part, that accounts for the widely observed tendency of teens to prefer to stay up late and sleep in in the morning.
First Published February 5, 2012 12:00 am
