This is the primary reason for an early start. Primary school, bussing schedules and athletics can shift.
This leaves the question: why does work start so early? If children benefit from sleeping longer, so should adults.
This leaves the question: why does work start so early? If children benefit from sleeping longer, so should adults.
People at different ages require different amounts of sleep in order to be healthy. Adults require less than children [0].
Also, one of the big problems for teenagers (the subject of the article) is that their circadian rhythm is out of phase from adults, shifted later about 2 hours [1]. Early start times don't just reduce sleep, they're also just the wrong time of day. Telling a teen to wake up at 7am is like telling an adult to wake up at 5am.
If you work 7-15h (3pm american), you still have some daylight time left at home, after work so you can do other, non-work stuff that requires daylight. If you sleep until 9 and work 10-18h, you get zero off-work daylight for most of the year.