Children and Adolescents Can Increase Their Sleep Time

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The movement to start schools later for post-pubertal children and adolescents has been successful by any measure. Many school districts have followed the recommendation of the American Academy of Pediatrics that middle and high schools should begin no earlier than 8:30 am. Among the major rationales for the AAP’s recommendation are (1) Due to a delay of release of melatonin by the pineal gland that evidently accompanies the onset of puberty, middle- and high-school students have great difficulty falling asleep early enough in the evening to get enough sleep before having to wake up for an early school start; (2) If start times are later, students will get more sleep; and (3) By getting more sleep, improvements will be seen in socioemotional behavior, attention and learning, and health.

Not enough time has passed for schools that have changed start times to determine if (2) and (3) will come to pass. Some skeptics have said that after students have gotten used to later start times, they will stay up even later and will sleep no longer than before the change. Others have suggested that changing start times will have little effect when so many other factors are responsible for insufficient sleep with the biggest culprit being the use of smartphones to access social media.

I have followed local news reports of a great many school board meetings, and one comment I have heard repeated many times is some variation of “All the science says we should start school later.” This conclusion is justified to some extent because so many consultants and lobbyists, many with scientific credentials, have repeatedly argued that the rationales listed above are sound and beyond question. But in this case, like so many others where people look to science to inform public policy decisions, when science is conducted properly, nothing should be beyond question.

A study recently published in Pediatrics, the peer-reviewed flagship journal of the American Academy of Pediatrics, addressed the premise of rationale (1). Ian Campbell and colleagues at the University of California, Davis used home-based polysomnography and actigraphy in an experiment with several cohorts of children and adolescents to see if they could increase their sleep by going to bed earlier. Collecting data over a period of three years allowed for looking at whether changes occurred in their ability to get more sleep with an earlier bedtime as they got older. For four consecutive nights, participants adhered to each of three time-in-bed schedules (7; 8.5; and 10 hours) while keeping their wake times constant. Even with increases in time taken to fall asleep and some increases in the number of short wake periods during the night, average sleep duration increased with more time in bed. With 7 hours in bed, they slept about 6.7 hours; that increased to 7.8 hours of sleep when they stayed in bed 8.5 hours, and to 8.8 hours of sleep when they stayed in bed for 10 hours. The findings proved that the ability to sleep longer with more time in bed did not change from the time participants were 10 years old to when they were 21.

You may be excused for thinking that it is remarkable that an empirical study was needed to prove what common sense tells you: If you go to bed earlier and stay in bed longer, you get more sleep. But as the authors point out, those who have argued for rationale (1) have said with great confidence that even if adolescents go to bed early enough to get sufficient sleep, they will just stare at the ceiling because they cannot fall asleep before about 11 pm. Obviously most adolescents will continue to stay up too late to get sufficient sleep no matter what time school starts. But at least there is evidence that there is no biologically based reason that they could not get more sleep with earlier bedtimes even when they have an early morning school start time.