Emerging research suggests that young people are sleeping less than ever before with the sleep void potentially damaging their physical and mental health.
Ironically, but perhaps not surprisingly, San Diego State University investigators discovered the decline in restorative slumber is linked to technology and because teens are trading their sleep for smartphone time.
Most sleep experts agree that adolescents need nine hours of sleep each night to be engaged and productive students; less than seven hours is considered to be insufficient sleep. However, a peek into any bleary-eyed classroom in the country will tell you that many youths are sleep-deprived, but it’s unclear whether young people today are in fact sleeping less.
Jean Twenge, a professor of psychology at San Diego State University, along with psychologist Zlatan Krizan and graduate student Garrett Hisler — both at Iowa State University in Ames, wanted to quantify how much kids are sleeping, and, if the hours are less than previous generations, then why the change?
To do this, the research team examined data from two long-running, nationally representative, government-funded surveys of more than 360,000 teenagers.
The Monitoring the Future survey asks U.S. students in the eighth, 10th, and 12th grades how frequently they receive at least seven hours of sleep, while the Youth Risk Behavior Surveillance System survey queries ninth to 12th-grade students on how many hours of sleep they obtain on an average school night.
Combining and analyzing data from both surveys, the researchers found that about 40 percent of adolescents in 2015 slept less than seven hours a night, which is 58 percent more than in 1991 and 17 percent more than in 2009.
Delving further into the data, the researchers learned that the more time young people reported spending online, the less sleep they got. Teens who spent five hours a day online were 50 percent more likely to not sleep enough than their peers who only spent an hour online each day.
Beginning around 2009, smartphone use skyrocketed, which Twenge believes might be responsible for the 17 percent bump between 2009 and 2015 in the number of students sleeping seven hours or less.
Not only might teens be using their phones when they would otherwise be sleeping, the authors note, but previous research suggests the light wavelengths emitted by smartphones and tablets can interfere with the body’s natural sleep-wake rhythm.
The study results appear in the journal Sleep Medicine.
“Teens’ sleep began to shorten just as the majority started using smartphones,” said Twenge, author of iGen: Why Today’s Super-Connected Kids Are Growing Up Less Rebellious, More Tolerant, Less Happy — And Completely Unprepared for Adulthood. “It’s a very suspicious pattern.”
Students might compensate for that lack of sleep by dozing off during daytime hours, adds Krizan.
“Our body is going to try to meet its sleep needs, which means sleep is going to interfere or shove its nose in other spheres of our lives,” he said. “Teens may catch up with naps on the weekend or they may start falling asleep at school.”
But, what’s a parent to do? Taking away a cell phone is an untenable action in today’s world as smartphones and tablets are an indispensable part of everyday life.
Researchers believe the key is moderation, Twenge stresses. Limiting usage to two hours a day should leave enough time for proper sleep, she says. And that’s valuable advice for young and old alike.
“Given the importance of sleep for both physical and mental health, both teens and adults should consider whether their smartphone use is interfering with their sleep,” she says.
“It’s particularly important not to use screen devices right before bed, as they might interfere with falling asleep.”