The influence of sleep and time of day on school performance: causes, consequences and possible remedies

Introduction:

Sleep is essential for health and performance and its timing and consolidation are regulated by the biological clock. There is a rich variety in sleep timing (chronotype) that is often disregarded by society when imposing uniform school/working starting times. This has consequences, for instance, for school performance. Previous studies have shown that late chronotypes (those who sleep late) achieve on average lower grades.

Materials & Methods:

We collected data about sleep (chronotype) together with grades and school attendance indicators at a Dutch high school. In another series of studies, we tested simple protocols to advance sleep timing by sleeping with open curtains (increased morning light exposure) and by wearing blue light blocking glasses in the evening (decreased evening light exposure). The goal was to help late chronotypes getting more sleep and better match their internal (biological) time to the external (social) time.

Results:

We found that the impact of chronotype on school grades was stronger in the early morning and for scientific subjects. In addition, late chronotypes were more often absent from class, which, in turn, was associated with lower grades. Our findings from the experimental studies show that simple „in-home“ light interventions are potentially effective in advancing sleep timing.

Discussion & Conclusion:

The findings of these studies have potential applications for society. Suggestions to improve school policies and practical solutions to delayed sleep phase are proposed.