🎓 Explosion of good grades just by pushing back the start time of classes

Teenagers often have a sleep rhythm that is shifted compared to adults, a biological particularity that inclines them to go to bed and wake up later. This natural tendency clashes with early school schedules, which can reduce their rest time and affect their overall well-being. Behind this common situation lies a notable influence on their development and learning capacity.

Faced with this observation, researchers from the University of Zurich examined a pragmatic solution: giving students the freedom to choose their start time for classes. Their work focused on a secondary school that implemented a flexible system, allowing students to start their day later. This initiative aims to better harmonize schedules with the physiological needs of young people.


To measure the impact of such a measure, the team collected responses from 754 students around 14 years old, via questionnaires distributed before and after the implementation of adjustable schedules. This data allowed them to evaluate changes in their sleep habits, well-being, and academic performance.

When given the opportunity, an overwhelming majority of 95% of students opted for a later start to the day. In practice, they started classes on average 38 minutes later than before. This change allowed them to wake up about 40 minutes later, thus increasing their sleep time by 45 minutes on school days, without significantly changing the time they went to bed.

In addition to prolonged sleep, participants reported a better quality of life and fewer problems falling asleep. Their academic results also improved, with noticeable progress in English and mathematics compared to regional averages. Published in the Journal of Adolescent Health, these results indicate that a simple adjustment of schedules can lead to several benefits.

Mental health difficulties among young people remain an important concern. In Switzerland, almost half of 11 to 15-year-olds experience recurrent psycho-affective disorders, such as sadness or anxiety. Adapting school schedules to the biological rhythm of teenagers could help reduce these trials, by encouraging a more favorable daily balance.

The circadian rhythm of teenagers

During adolescence, the body undergoes transformations that affect the internal clock. The production of melatonin, the sleep hormone, naturally shifts to later hours. This phenomenon makes young people more alert in the evening and more tired in the early morning.

This shift is linked to hormonal changes and brain development. It explains why many teenagers have difficulty falling asleep early, even when they try to go to bed at a reasonable time. Their biological rhythm is simply programmed differently from that of adults.

Understanding this mechanism helps to grasp the daily obstacles encountered by students. Traditional school schedules, designed for adult rhythms, often contradict this physiological reality. This can lead to chronic sleep deprivation with multiple consequences.