Delaying the start of classes in lower secondary schools - a French experiment

Abstract

After the age of 12, bedtimes become later as a result of a physiological delay in circadian phase. The use of screens in the evening contributes to this shift, but is not sufficient on its own to explain it. Due to early school start times, adolescents are chronically sleep deprived, even though sleep is known to be closely linked to cognitive performance and emotional regulation.

Research findings are consistent: delaying the start time of classes improves sleep duration and, as a result, students’ wellbeing and academic outcomes. This measure is therefore now considered one of the most robust recommendations, based on data from sleep science, chronobiology, and developmental psychology, in the fields of public health and education policy.

This note was written by Stéphanie Mazza, Eve Reynaud, Alexandre Grellet, Marc Gurgand, Adrien Pawlik, and Amandine Rey.