Recommendations for how much sleep children of different ages should get are based on a consensus of professional judgement. Age groupings are essentially arbitrary, and for each age group, there is a range of hours, reflecting that there are individual differences in need for sleep. Other than knowing that on average, older children are observed to sleep fewer hours than younger children, only rough estimations of need can be made. I recently summarized results of a meta-analysis of studies that used objective measures (actigraphy) and found that sleep duration averages for all age groups were toward the lower end of recommended ranges (Galland et al. 2018).
In a new study by Gruber and colleagues (2018), it is noted that sleep recommendations by the National Sleep Foundation (NSF) for children in elementary and middle school are the same: 9 to 11 hours. The assumption is that sleep needs do not change between the ages of 6 and 13. But when they measured sleep objectively children between ages 6 and 11 on seven consecutive weekday nights during the school year, they found that older children within that range were sleeping much less. For example, only 51.3% of children ages 10 and 11 were spending 9 to 11 hours in bed. Actigraphic measures of “true sleep” showed even fewer children at any age getting the recommended hours of sleep.
So the question remains: Do older children “need” less sleep than is recommended or are a great many elementary age children just not getting enough sleep? There is really no way to answer the question definitively, but my opinion leans toward the latter interpretation. I was intrigued by the following comment by Gruber et al.:
“Collectively, the findings show that changes previously assumed to occur around adolescence, with the onset of puberty, can instead be detected among younger, school-age children. The sleep of children as young as third and fourth grade is already delayed, shorter, and more variable than that of their younger counterparts, and this becomes more extreme among fifth and sixth graders.”
Since Mary Carskadon’s pioneering studies in the 1980s, it has been virtually a canon of sleep science that postpubertal adolescents experience a phase delay, having a difficult time going to sleep early. Because high schools have started so early in the morning, teens are assumed to be chronically sleep deprived.
That assumption is the primary scientific foundation for the growing movement to push back high school start times. As I have written about before, school districts that make the difficult decision to make high school start times later have “flipped” the bus schedules such that elementary schools start earliest. There is very little research to determine if earlier start times for elementary students result in them getting less sleep, and also little research to determine if their academic performance is negatively affected.
But the Gruber et al. results and conclusions at least should give us pause. If children are sleeping less as they age into the 6 to 11 range, it is probable that while the vast majority of the older children (10 and 11) are prepubertal, they are still sleeping an insufficient number of hours. Gruber et al. did not report what time schools of children in their sample started, but they do report waking up at times between 6:18 and 6:30 a.m. When elementary schools start as early as 7:30 a.m., children must wake up very early to allow for dressing, breakfast, and transportation to school. While it is understandable that the American Academy of Pediatrics has recommended that middle and high school start no earlier than 8:30 a.m., is there really any justification for not extending that recommendation to elementary schools?
Source: Psychology Today