Because most high schools have an early start time, students are able to participate in more after school activities. 

When a high school has an early start time, that means that their release time is earlier as well. This ensures that teens get to take part in any sort of extracurricular activities they want since the time allows it. If a teen wants to work a job and play a sport at the same time, getting out of school early will allow them to do both.

In addition, if children got out of school later due to a later start time, after school sports activities would be pushed back later into the evening, which would force teens to stay up late into the night.

Oftentimes, multiple teams must share one field or court for their practices and games. The time must be divided up among all of the teams to each have usage of the area. If the ending time were to be later, then the amount of time that teams would get on the field would be lessened or extended later into the night. 

This would cause either scheduling to be more complicated, or it would force teens to have late night practices, which would cause them to get less sleep at night.

The early start time also allows teens to help out with younger siblings.

Most times, working parents are at work while their younger children are arriving home from school. Many parents rely on their teens to watch over younger children during the afternoon. This would not be possible without the early start time of high schools.

An early start time also gives teens more free time in general.

Getting out of school early gives teens basically their entire afternoon to enjoy. On non-school days, many teens won’t wake up until close to the end of school anyway. This means that very little of their day is wasted while being at school, since the time they finish school and the time they would wake up regardless is similar. 

Overall, the current high school start time benefits not only teens but also their families.

Oftentimes, first-period classes are full of zombie-like students. If school started later, that would be different. 

Waking up early and immediately diving into rigorous courses can be difficult. High school students require more sleep than adults, as they are actively developing, and sleep deprivation can be harmful to them.

High schools starting early in the morning can contribute to this harm, as students cannot get as much sleep.

Most teens have jobs and after-school activities that require them to get home late at night, leaving them little time to do homework and eat, let alone have any time for themselves. If they were to come home and immediately rush to do their homework and head to bed, they would have no time to unwind and enjoy time to themselves. 

This cannot only be harmful to their physical health, but also to their mental health, as they are constantly working with no time to relax. 

Also, most elementary children are awake when the high schoolers start, so they should start earlier. This way, the teens can help get siblings on the bus or drive them to school, and still have time to sleep and get ready for school. 

Starting school later would also provide more time for students to eat breakfast and get ready before school. Most high school students skip breakfast for the sake of time, so giving them more time in the morning would prevent that. 

A lot of students also struggle to get fully ready for school, as they want to sleep until the last minute, leaving them to quickly throw an outfit on and walk out the door. If they had more time, they could still get more sleep, and also not feel so rushed, making them feel more put together. 

Overall, later start times can improve teens’ physical and mental health, giving them more time to sleep, eat, and get ready.