In Germany, and also in many other countries, the students should be in their seats in the classroom by eight o'clock at the latest - the lesson begins. Some students even have a "zero lesson" that starts even earlier. This is often torture for the children and young people, because their biorhythm is different from that of adults. They need more sleep, and especially in the case of adolescents, the hormones ensure that they hardly ever doze off before 11 p.m.
What parents often dismiss as laziness or their own fault on the part of the teenagers ("Then don't go to bed so late!") is something that pubescents really can't do much about. And they suffer particularly from the rigorous early start of classes. Since they have to get up early every day, but still do not get tired earlier in the evening due to their hormonal biorhythm, an unhealthy sleep deficit gradually accumulates. Many young people do not get the eight to ten hours of sleep that would be necessary at this age.
Several studies show what the traditional school system and the current form of capitalism do to the tired children: With a regular lack of sleep, students learn less well, are less able to regulate their emotions and are even less helpful. Lack of sleep also makes us more susceptible to illness and more likely to become overweight.
Source: "The Standard"