More than 90 percent of American high school students are chronically sleep-deprived, putting their health and academic performance in jeopardy, a new report finds.
Too-early school start times are one big factor, experts say.
Teens face a number of challenges
The study, based on U.S. national data, finds that most teens don't get the minimum 9 to 10 hours of sleep per night that's recommended by standard guidelines.
Teenagers do face a number of challenges as they try to get adequate sleep, experts say.
Read: Sleep apnoea may lower your aerobic fitness
"I don't believe there's one culprit," said the study's lead author, Charles Basch, a professor of health and education at the Teacher's College at Columbia University in New York City.
"For some children it's too much homework, for some it's health problems like asthma," he explained.
"For others it may be anxiety or depression, or the prescription medications they are taking for such conditions. Recreational drugs can be a factor, as can having electronics in the bedroom."
Whatever the reason, government surveys show that poor sleep is an ongoing issue for most teenagers.
"This type of data has only been collected since 2007, so we can't say whether the situation has been getting worse historically," Basch said.
"But what we can clearly say is that a very substantial portion of high school students throughout America is not getting enough sleep."
Adequate sleep is crucial
His team noted that teens, especially, need adequate sleep because it's crucial to memory, attention, emotional well-being and overall physical health.
In the study, the researchers tracked findings from four U.S. government surveys conducted in 2007, 2009, 2011 and 2013 as part of the Youth Risk Behaviour Surveillance System.
Each year, between roughly 12 000 to 15 000 students in grades 9 through 12 were asked about how many average hours of sleep they got each school night.
Overall, less than 10 percent of teens said they were actually meeting current U.S. Centres for Disease Control and Prevention guidelines for sleep.
Only about 7 percent of girls, and around 8 to 9 percent of boys said they got nine to 10 hours of sleep per night.
Read: How well you sleep may depend on your genes
And, for the most part, sleep patterns for teenagers appeared to get worse with age – surveys showed that by the time they reached 12th grade, a whopping 95 percent of high school seniors were not routinely meeting CDC sleep guidelines.
Girls tended to fare worse than boys, with girls being more prone to sleep five hours or fewer per night and less likely to get nine or more hours of sleep each night, the study found.
Race also appeared to figure into the equation: black teenagers were significantly more likely to get five or fewer hours of sleep per night than their white peers.
In each survey, 20 percent of black boys and girls were found to have daily sleep routines that included five or fewer hours of sleep. The same was true of 15 percent of Hispanic girls and about 12 percent of Hispanic boys.
School start times a major factor
According to Basch, early school start times are one major reason behind all those sleepless teens.
"More and more attention is being focused on the start times of schools, with the idea being that very early class schedules do not serve good sleep patterns," he said.
"That is certainly one of the problems," agreed Kelly Baron, an assistant professor of neurology and director of the Behavioural Sleep Medicine Program in the department of neurology with the Feinberg School of Medicine at Northwestern University in Chicago.
She called the data from the new report "alarming".
"While we're still trying to understand why this is happening, one of the reasons is clearly school start times," Baron said. "Having children wake up to start school at 6 or 7 a.m. is really at odds with their biology."
She explained that a person's sleep patterns "naturally change across our lifespan. And one of the most profound changes is that our natural 24-hour rhythm shifts as we enter puberty. Sure – some of it's social, [and] kids just want to stay up late and such. But the need to stay up later and sleep in later is also biological. So early school times set them up for a chronic sleep disadvantage."
So, can parents do anything to encourage more shut-eye for their kids?
Read: How post traumatic stress disorder affects sleep
"They can and should get involved," Baron said, "setting curfews, establishing sleep schedules, and limiting screen time in the bedroom. A healthy sleep environment at home is key."
The new study is published in the CDC journal Preventing Chronic Disease.
Just how much sleep is enough?
What happens when you fall asleep?
Good sleeping habits
Image: Sleepy teen from Shutterstock.
Copyright © 2016 HealthDay. All rights reserved.