Two recent studies published in the Journal of Clinical Sleep Medicine highlight the importance of adequate sleep in teenagers. Both studies evaluated the effect of school start times.
In one study, conducted in Israel, the start of the school day was delayed by one hour for one week. A control group did not have their day delayed. After one week the eighth-grade students in the experimental group performed significantly better on two different tests of attention.
In the other study, motor vehicle crash statistics from a pair of neighboring communities in Virginia with different high-school start times were compared. The community with the earlier school start times (by approximately seventy-five minutes) had significantly more teen automobile accidents. This is consistent with an earlier study, also published in the Journal of Clinical Sleep Medicine, in which a one hour delay in high school start times was associated with a decline in teen crashes.
A limitation of these studies is that sleep per se was inferred but not measured. They do, however, illustrate the kind of practical changes that can lead to real improvements in health, safety, and performance.