A few years ago, Kari Oakes of Annapolis, Maryland, was excited to be sending her first child to high school — until she saw her daughter's schedule. “I thought there was a typo,” she said. The bus would pick her daughter up at 6:25 a.m. to get her to school in time for the first bell at 7:17 a.m. Little did Oakes know that compared to other school districts, her daughter's was being generous. Busses in some states were picking up children just after 5:00 a.m.

Smartphone showing school bus picking up kids at 5:10 a.m in Anne Arundel County, MarylandSmartphone shows school bus pick-up at 5:10 a.m. in Anne Arundel County, Maryland (Photo: Lisa Van Buskirk/Start Schools Later)

As a physician assistant, Oakes knew such an early start wasn’t good for her daughter, who would have to be up by 5:30 a.m. This meant she’d have little chance of getting the amount of sleep recommended for kids her age.

“I knew I was harming my daughter’s health when I woke her up every morning to get on that bus," Oakes recalls, "but I had to do it or I would end up in truancy court.”

In the years since, Oakes has become more than a concerned mom. She’s now co-director of research and development for Start School Later, a nonprofit organization working to help public schools set hours that are compatible with children’s health, safety and learning.

Related: How to Keep Your Kids Safe at the Bus Stop

“Early to bed, early to rise” doesn't work for teens

Researchers have long known adolescent brains are wired to go to sleep later and get up later than those of other people. Beginning at puberty, kids’ sleep-wake cycles begin to shift up to two hours later, according to the American Academy of Pediatrics (AAP). So it’s not just hard for them to get up in the morning, it’s tough for them to get to sleep before 11:00 at night.

Experts say teens need at least nine hours of sleep to be at their best. By the end of high school, though, they average fewer than seven hours per night, reports the National Sleep Foundation (NSF). A poll by the organization found 59 percent of 6th through 8th graders and 87 percent of high school students in the U.S. were getting less than the recommended 8½ to 9½ hours of sleep on school nights.

When they're short on shut-eye, teens are at an increased risk for car accidents, aggression and violence, tobacco and alcohol use and poor performance in everything from academics to sports, according to the NSF.

It's small wonder the AAP has weighed in on the issue. It recommends middle schools and high schools begin no earlier than 8:30 a.m. The Centers for Disease Control and Prevention (CDC) also has pushed the snooze button on early school start times, saying they have a negative impact on kids’ health.

A wake-up call for schools

With experts from the AAP, CDC and other leading health organizations behind later school times, not to mention exhausted students and their parents, you might expect that schools would be opening later these days. The reality: Only 15 percent start at 8:30 a.m. or later. An estimated 43 percent of high schools in the U.S. start before 8 a.m. The bell rings before 7:30 a.m. in 10 percent of high schools.

And yet, several benefits of later start times for high schoolers have been proven. A 2014 study by researchers at the University of Minnesota found that schools that switched to a later schedule saw improved health and grades among their students. The three-year project collected data from 9,000 students at eight schools in three states. When the schools switched to a later start time, test scores, academic performance and attendance all improved. Meanwhile, reports of substance abuse, depression and tardiness declined. In Jackson Hole, Wyoming, the number of car crashes involving high school drivers fell by 70 percent after the school district moved the high school start time to 8:55 a.m.

Harnessing parent power

Here are some steps you can take to help your child log enough sleep.

Establish a regular “lights out” time. Child and teen therapist Barbara Greenberg of Fairfield County, Connecticut, says this gives teens the excuse they need to get off social media and finish their homework.

Related: How to Help Your Teen Get Enough Sleep

Stick to the regular sleep routine on weekends. Teens love to stay up late and sleep late on weekends, but experts say it’s better for their health to go to bed at roughly the same time.

Limit outside activities if your child isn’t getting enough R&R. Kids need at least 45 minutes a day to decompress, which will make it easier for them to sleep, says Greenberg.

Encourage your teen to cut the caffeine. Guzzling beverages such as energy drinks, tea and iced coffee can make falling asleep difficult.

Keep computers and other screens out of your kid's bedroom. It's better to remove that temptation from the sleep area altogether, advises Greenberg.

Related: Block Blue Light and Sleep Better Tonight

Get involved in efforts to encourage your school district to make school start times later. This approach can work. The NSF reports that schools or districts in 19 states have pushed back their start times, and more than 100 school districts in an additional 17 states are considering doing the same.

For Oakes and her kids, the days of a 5:40 a.m. wake-up call are over. This year her family moved to Middleton, Wisconsin, where the top-rated school starts at 8:25 a.m. Her daughter has already graduated, but her son gets to sleep in.

Mary Purcell is a freelance writer and health researcher in Piedmont, Calif., with expertise in policy analysis. She has a master's degree in Latin American studies from Georgetown University.