Why letting teens sleep in could save lives

The reason your teen sleeps till noon
The reason your teen sleeps till noon

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The reason your teen sleeps till noon 01:16

Story highlights

  • Teens who get less than seven hours sleep a night are more likely to engage in risky behaviors, study says
  • One way to help teens get more sleep is to give them later start times at school, doctors say

Kelly Wallace is CNN's digital correspondent and editor-at-large covering family, career and life. Read her other columns and follow her reports at CNN Parents and on Twitter @kellywallacetv.

(CNN)Ask parents of teenagers what they're worried about, and among the issues they're likely to bring up is their teens not getting enough sleep. So many teens stay up past midnight and get up early, especially when their school starts, in some cases, well before 8:00 a.m.

A new study finds that pattern is not only dangerous -- it could be deadly.
    The study by the Centers for Disease Control and Prevention found that teens who get less than seven hours of sleep on school nights were more likely to engage in risky behaviors -- such as texting and driving, drinking and driving, riding with a driver who was drinking, and not wearing a seat belt in a car or a helmet while on a bicycle -- than teens who sleep nine hours a night.
    "It was rather surprising to find such an impact of short sleep duration on these injury-related behaviors and suggests that sleep deprivation may play an important role in poor judgment and decision-making among adolescents," said Janet Croft, chief of the epidemiology and surveillance branch of the National Center for Chronic Disease Prevention and Health Promotion at the Centers for Disease Control and Prevention and one of the co-authors of the study.
    This current CDC report, which analyzed questionnaires from more than 50,000 high school students in 2009, 2011 or 2013, is just the latest research to document how worrisome a lack of sleep for teens can be.
    Back in 2011, the CDC found that insufficient sleep for teens, which was described as less than eight hours on average a night, was associated with cigarette, alcohol and marijuana use, sexual activity, not getting enough exercise, feeling sad or hopeless, and seriously considering attempting suicide. Almost 70% of teens were not getting enough sleep, the CDC found.
    Doctors around the country grew so concerned about the impact of a lack of sleep on teens, including the connection with obesity, depression and traffic accidents, that the American Academy of Pediatrics issued a policy statement in 2014 recommending that schools start no earlier than 8:30 a.m. so that teens can get the recommended 8.5 to 9.5 hours of sleep a night.
    But last year, researchers from the CDC and the U.S. Department of Education found that, based on data from the 2011-2012 school year, only 18% of the schools surveyed started classes at the recommended time of 8:30 a.m. or later, while more than 80% started earlier. Students in Louisiana were found to go to school the earliest with an average start time of 7:40 a.m.

    'Our society does not respect sleep'

    Think about this: If you have to be at school at 7:40 a.m., and you have a 30-minute commute and need at least 30 minutes to have breakfast, shower and get out the door, you must be up at 6:40 a.m. at the latest. If you want to get the recommended 8.5 to 9.5 hours of sleep, you need to be in bed between 9:10 p.m. and 10:10 p.m. Do you know any teens who go to bed that early?
    "The real issue at this point is that our society does not respect sleep, and we have grown-ups that brag about how, 'We can get on with five hours of sleep,' 'We can drink that Red Bull and soldier on,' 'Sleep is for wimps,' 'I'll get enough sleep when I'm dead,'" said Maribel Ibrahim, co-founder of Start School Later, a nonprofit focused on increasing public awareness about the relationship between sleep and school hours. "These are the statements that are horrifying, because really sleep is an essential third pillar of health."
    For way too many years, I've gotten too little sleep. From 4:00 a.m. wake-up calls during my days covering the White House, to sleeping just three hours at a stretch when I had my girls, to early wake-ups even now, I still don't regularly get enough sleep -- but I see the difference when I do. I'm fresher, quicker and all-around better at my job and as a parent when I get more sleep, and that is the case with teens, too.
    A study by the University of Minnesota of more than 9,000 students in eight public high schools from three states found that schools with start times of 8:30 a.m. or later report improved academic performance in core areas such as math, English, science and social studies, better scores on state and national achievement tests, improved attendance and a reduction in tardiness.
    Rock Bridge High School in Columbia, Missouri, moved up the start time for the school day from 7:50 a.m. to 8:55 a.m. at the beginning of the 2013-2014 school year.
    The school has not done any study on the impact of the later start time, but anecdotal evidence from parents does point to some improvement, said Jennifer Rukstad, the school's principal.
    "There was just lots and lots of complaining about the impact on the life of the family, and so once you kind of allowed that to get through, then if you would ask the parents what kind of impact has it had on your child as far as their affect and their performance. And everyone said, 'Oh, they're much easier to get along with,'" Rukstad said.
    "A teenager is going to go to bed when they go to bed, no matter what time they are supposed to get up, so if they're going to stay up until midnight, they're going to stay up until midnight whether school starts at 7:50 or 8:55. So they are, in general, getting a little more sleep than they were before, because they don't have to get up as early," she said. "But I have no data that says that performance has gone up, that we've dropped depression rates. We just don't have data on that."
    The experience at Rock Bridge also points to the challenges of implementing later start times at every school around the country. The school day at Rock Bridge ends at 4:05 p.m., which affects athletic teams that need to travel a distance for games and after-school clubs. After-school clubs are not nearly as popular as before-school clubs, Rukstad said.
    People generally love the start time, but hate the end time, she added. It's possible, she said, that at some point in the next few years, based on financial pressures, busing needs and teaching demands in the district, the school time at Rock Bridge might move back to a slightly earlier time, but not as early as 7:50 a.m.
    "There are just some limitations, especially when you look at middle school and high school of having their schedules so vastly different," said Rukstad. (Middle schoolers start their day at 7:30 a.m.)

    'The enemy is ignorance'

    Ibrahim of Start School Later said more schools are moving in the direction of starting later. When her group was formed in 2011, she said, schools in a total of 23 states attempted to begin the school day at a later time. Today, schools in 44 states have made the move, she said.
    "So it is becoming a conversation piece. People are talking about it, and right now we have school districts that have done it," she said. "All the previous obstacles that were cited are really not obstacles at all. The biggest obstacle is fear of change."
    Just this week, Maryland passed legislation which will recognize schools that are making strides toward healthy hours, said Ibrahim. "It's really going to bring even more attention to the problem and it's going to support school districts that are really trying to make a change," she said.
    What can a parent do? Researchers at the CDC say parents can encourage their children to practice good sleep habits, such as setting a regular bedtime and wake-up time, including on weekends, and limiting the use of devices such as computers, video games and cell phones in the bedroom after a certain hour.
    "Parents may benefit themselves and their children by setting a good example," said Anne Wheaton, an epidemiologist with the Centers for Disease Control and Prevention and a co-author of the new study. "Adolescent sleep habits tend to reflect their parents' sleep habits."
    The greatest thing parents can do to help their teens get more sleep, according to Ibrahim of Start School Later, is really get educated on the issue of school start times. "Ironically, even well-meaning school districts that have attempted to implement school start times have gotten backlash from the community, from the parents, because the school districts are not the villains necessarily. Really the enemy is ignorance," said Ibrahim. "The enemy is assuming, 'Oh this isn't that big a deal. Just turn off your devices at night and stop texting and all will be well.' That would be great if kids could get up at 7:30 in the morning, but it's not great when they still have to get up at 5:00."
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    It will be years before my girls, 8 and 10, begin high school. But after going through the research, hearing the benefits of later school start times, and knowing how difficult it is to get a teen to go to bed early despite a parent's best intentions, I'm hoping by the time they get there, later start times will be as normal in high school as a teenager's eye roll.
    "We'll say, 'Oh my gosh, they used to start school at what time?'" joked Ibrahim.
    Do you think high schools should have later start times? Share your thoughts with Kelly Wallace on Twitter @kellywallacetv.