Teens are nocturnal creatures. They tend to stay up late at night, struggling to wake up refreshed in the morning with enough time to get ready for the day.

In fact, about 87% of high school students don’t get enough sleep, averaging less than seven hours a night. What’s more, about 28% of high school students fall asleep during class at least once a week. One in five also report falling asleep while doing their homework at a similar frequency.

With the new school year revving up, experts from the American Academy of Pediatrics declared that teens’ chronic tiredness is a public health issue. On September 1st, they issued a policy recommendation to middle and high schools, arguing that they should delay their start times until 8:30 a.m. at the earliest so that teens can get more sleep.

“A substantial body of research has now demonstrated that delaying school start times is an effective countermeasure to chronic sleep loss,” argued the organization. “The American Academy of Pediatrics strongly supports the efforts of school districts to optimize sleep in students.”

Sleep deprivation can cause a myriad of health, social, and academic problems. According to a statement from the Academy published in Pediatrics, teens who get less than 8.5 hours of sleep a night are at a higher risk of obesity, diabetes, mood changes, and behavior problems. Sleep deprivation can make a person irritable and unfocused, having negative repercussions on his or her relationships and quality of work.

After reviewing and analyzing all of the studies to date on how inadequate sleep can affect teens, the Academy concluded that there was enough evidence to support pushing the start times of schools back to 8:30 a.m. at least.

Some studies showed that even just a half-hour delay can drastically improve students’ health and academic performance.

“The hope is that this statement will galvanize communities,” said Dr. Mary Carskadon, a Brown University Medical School professor of psychiatry and human behavior. “Now they have another tool in their tool kit, and another set of evidence and advice to take to school committees and school boards, to get communities moving on addressing adolescent sleep.”

“To do nothing is really to do harm,” said Dr. Judith Owens, the Children’s National Medical Center’s director of sleep medicine. “The status quo of starting schools at 7:15 or 7:20 is not in the best interest of the students.”