Matthew Walker’s book “Why we sleep” discusses how our sleep patterns change as we age and how vital it is for teenagers to get sleep. Another quicker read is

Matthew Walker’s book “Why we sleep” discusses how our sleep patterns change as we age and how vital it is for teenagers to get sleep. Another quicker read is here: Chronotype and Adolescence: Why being an "evening person" as a teenager is disadvantageous [https://www.psychologyinaction.org/psychology-in-action-1/2017/11/30/chronotype-and-adolescence-why-being-an-evening-person-as-a-teenager-may-be-disadvantageous https://www.psychologyinaction.org/psychology-in-action-1/20...] Basically, even for those who don’t have a night owl chronotype, our sleep shifts back during adolescence. We now know how important sleep is for learning and memory consolidation. Having schools stagger start time for different cohorts based on preference sounds like the most obvious answer to me to alleviate the problems caused by imposing early start times on all students. One size fits all is hardly ever the best solution.