We've known this for decades, but almost no districts will make the changes necessary. The youngest grades (K-4 or 5) should be the first schools to start in the morning, and the HS the last.
What happens when that is suggested is people balk at either sports programs needing to be cut or the argument that the older siblings need to be out of school to babysit the younger siblings.
I had to teach a zero period jazz band when I student taught. Waking up that early to drive the 45 minutes suuuuuckkkked