American pediatricians are urging later school day start times for teens, saying it will help improve mental and physical health, as well as academic performance.

In a policy statement released Monday, the American Academy of Pediatrics said delaying the start of classes until at least 8:30 a.m. will help curb sleep deprivation among teens.

Studies have found that most U.S. students in middle school and high school don't get the recommended amount of sleep on school nights, yet more than 40 per cent of U.S. public high schools start classes before 8 a.m.

Teens are “biologically programmed to fall asleep at 11 and wake at around 8 a.m.,” said Dr. Judith Owens, a paediatrician with Children’s National Medical Center. “And that's a time when they're already in first period class."

Canadian teens face similar problems. Surveys show that up to 70 per cent of Canadian students say they are often very sleepy during morning classes.

“They need between 8 ½ and 9 ½ hours of sleep,” said Judith Davidson, a psychologist at Queen’s University in Kingston, Ont.

U.S. pediatricians say teenage brains are in flux and a surge of hormones makes them stay up later. Some researchers compare teenagers’ sleep patterns to a permanent state of jet lag that can lead to anxiety, depression, weight gain and even an increase in car accidents.

In Canada, most high schools start their days between 8 a.m. and 8:45 a.m. But one Toronto school, Eastern Commerce Collegiate Institute, is experimenting with a 10 a.m. start.

“We have seen improvements in areas of student achievement, in areas of lower absenteeism rates,” said school principal Jennifer Chan.

Still, some parents say teens can get the required amount of sleep each night with just a little bit of discipline. Many of them say smartphones, laptops and other electronics are what really keeps teenagers awake at all hours of the night.

With a report from CTV’s medical specialist Avis Favaro and senior producer Elizabeth St. Philip and files from The Associated Press