*The following is excerpted from an online article posted on HealthDay.
Most American teenagers are plagued by too little sleep, which can hurt their health and their school performance, federal health officials said.
Nearly 58 percent of middle school students in nine states and almost 73 percent of high school students across the country don't get the recommended amount of nightly shuteye, according to a report from the U.S. Centers for Disease Control and Prevention.
"Children and adolescents who don't get enough sleep are at increased risk for obesity, diabetes, injuries, poor mental health, and attention and behavior problems, which can affect them academically," said report author Anne Wheaton, a CDC epidemiologist.
According to the American Academy of Sleep Medicine, children aged 6 to 12 need nine to 10 hours of sleep a night, while teenagers aged 13 to 18 should get at least eight hours per night, she said.
One sleep expert has a theory on why so many teens are short on shuteye.
A big part of the problem is that teens stay up late using smartphones and computers, playing video games or watching TV, said Dr. Thomas Kilkenny. He is director of sleep medicine at Staten Island University Hospital in New York City.
Wheaton added that then kids have to get up early to get to schools that often start before 8:30 a.m. "One way for kids to get more sleep is to delay school start times," she suggested.
Switching to later school start times has been recommended by the American Academy of Pediatrics, the American Medical Association and others, Wheaton said.
In addition, parents can help their children practice good sleep habits. "These are things like having consistent bedtime and rise time, and that includes not just during the week, but on the weekends," Wheaton said. "That's good for everybody -- the adults, too."
Studies have shown that teens who have bedtimes set by their parents get more sleep than those who don't. Parents can also consider a media curfew or removing technology from the bedroom, she added.
"Adolescents who are exposed to more light in the evenings are less likely to get enough sleep, and using media can contribute to having later bedtimes," Wheaton explained.
Parents should also set a good example, she advised. If children see their parents placing a priority on sleep, then they're more likely to do the same.