48 minutes of extra sleep can improve academic engagement

The start of a new school year brings back to the forefront the issue of school start times. In spite of a policy statement from the American Academy of Pediatrics recommending that high schools begin no earlier than 8:30 AM, many middle and high schools still start much earlier than the recommendation. However, the Cherry Creek School District in Colorado decided to run an experiment with later start times, with the results recently being published in Sleep.

Beginning in Fall 2017, the Cherry Creek School district delayed the school start times for the middle school from 8:00 AM to 8:50 AM and the high school from 7:10 AM to 8:20 AM. The students in grades 6 to 11 were asked to complete online surveys during school hours in Spring 2017 (n=15,700) and in spring 2018 (n=18,607). The survey asked about the weekday and weekend bedtime (BT), total sleep time (TST), wake time (WT), academic engagement, sleepiness while doing homework, and extracurricular participation.

Researchers found the middle school students said that they had a slightly later BT (8 minutes), later WT (39 minutes) and longer overall TST (31 minutes). Among the high school students, there was a marginally later BT (13), a significantly later WT (61 minutes), and longer overall TST TST (48 minutes). Middle school students who received free/reduced lunch had more sleep duration than those who didn't (19m vs 10m, p=0.05), but no difference was seen in the high school students. Following the delayed school start time initiation, weekend oversleep went down by 38 minutes for middle school students and 59 minutes for high school students. More students also had sufficient sleep: middle school (≥9 hours), 38% versus 44%; high school (≥8 hours), 27% versus 58%.

The delay in start time did see an 8% decrease in sport participation in middle school students. Other activities in middle and high school, high school sports participation, and high school employment saw decreases of <3%. On the positive side, not as many students reported feeling too sleepy to complete homework assignments (middle school [46% vs 35%] and high school [71% vs 56%]). The measure of academic engagement was also significantly higher following the change in the start time as well for both groups of students (p<0.001).

The researchers concluded that middle and high school students would benefit from a later start time. The increased TST of 31 minutes for middle school students and 48 minutes for high school studies led to improved academic engagement and less sleepiness while doing educational work, all with little impact on extracurricular participation overall.