For the U.S. city, it was a small Revolution: For a good two years of teaching begins in all the 18 public high schools and most middle schools in Seattle not more to ten before eight, but only at a quarter before nine – with amazing effect.

Not only the parents had to be convinced of this. Also the schedule of the school buses was changed. And from the sports club to the school of music staff to the new starting times were set in the afternoon – all in the hope that the young people appear in the morning, fitter to class.

The changes have paid off, and the students are more alert. The scientists have found the University of Washington and the Salk Institute for Biological Studies, a small group of students. Their results have been published in the scientific journal “Science Advances”.

34 minutes more sleep

“The study shows a significant improvement in sleep duration of students,” said the study’s author, Horacio de la Iglesia. Accordingly, the Teenager sleeping in the middle much longer, the Median increased by 34 minutes. This means that half of the students sleep through the changeover of the week, each night a minimum of seven hours and 24 minutes. Prior to the Change of the Median was six hours and 50 minutes per night.

For the study, the scientists compared 14 days of sleep patterns from around 90 students from two high schools and the conversion of the School to commence. The data were collected with Fitness bracelets, worn by the study participants at the wrist. You captured every 15 seconds, the activity of the subjects and the lighting conditions.

Accordingly, has not moved to go to bed time of most of the students due to the later start of School to the rear. The ringing of the alarm clock. Consequently, they got more sleep.

The inner clock of young people dances to a different beat

“Previous studies have shown that the internal clock of adolescents differs fundamentally from those of adults and children,” explained Co-author Gideon Dunster. The change in the sit-to-stand time corresponded more closely to the rhythm of teenagers.

While the sleep timer will time biologically, due to the alarm, in social, says Dunster. The young people are ripped too early from sleep, was having a negative impact on your health and your well-being, said the student of biology. Also their attention span, suffer from the lack of sleep.

Altogether the Problem of lack of Sleep in adolescents is not solved by the later start of School in Seattle. Scientists recommend sleeping for the age group of eight to ten hours. Also, the subjects are removed from this study.