Starting school early might not be good for kids’ health.

A recent statement by the American Academy of Pediatrics said that delaying classes to 8:30 a.m. or later would help to counter chronic sleep loss in teens, who, according to medical experts, should sleep 8.5 to 9.5 hours every night. Only one in five teens end up sleeping that long on school nights, according to the National Sleep Foundation, and few public high schools (15 percent) already follow that recommendation, according to the U.S. Department of Education.

The effects of sleep loss aren’t just grogginess. Children and teens who don’t get enough sleep are more at risk for low levels of activity, obesity and diabetes as well as anxiety, stress and depression.

Lack of sleep affects academic performance as well as a student’s health. Teens who don’t get enough sleep are less likely to be motivated, focused and show up on time.

Tardiness in Philadelphia

In states like Pennsylvania, schools are not required to provide transportation for students. Philadelphia, for example, is considering cutting public transit subsidies for 7,500 high school students who live between 1.5 and 2 miles from school. Superintendent William Hite said that one of the major drawbacks of the decision would be a rise in truancy and lateness as teens struggled to wake up earlier and find a way to get to school on time.

In the United States, tardiness is one of the leading causes for suspensions, which disproportionately affect non-white students and increase the likelihood of dropping out of school. In 2010, 93 percent of suspensions for minor infractions like dress code violations, lateness and talking in class affected non-white students. Statistics from the same year found that Latino students dropped out of school at a rate three times that of their white peers and Black students dropped out at a rate two times of their white peers, according to the Department of Education.