Sleep and overall well-being for teens also improve.

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Getting enough shut-eye is especially important for teens. Getty Images

It’s Monday morning and your teenage son or daughter stumbles to the breakfast table like a grumpy zombie.

It’s not their fault — blame biology.

As kids hit puberty, their bodies go through a host of changes, including those that affect their sleep schedule. Not only do teens need more sleep in general, but their sleep cycles also shift later, which means waking up later.

Unfortunately, one thing that doesn’t change with them is the school day.

So, while your teen can likely sleep until 8 or 9 in the morning, the first school bell is usually ringing well before then.

But research increasingly suggests that starting school later in the day — adjusting start times by as much as an hour — can have significant positive effects on teens, from their brains to their bodies.

Preliminary findings from a new study by the American Academy of Sleep Medicine found that delaying school start times for middle school and high school students led not only to longer periods of sleep, but increased academic engagement.

The study took place in the fall of 2017 and included more than 15,000 students in grades 6-11 from the Cherry Creek School District in Greenwood Village, Colorado.

School officials voluntarily delayed school start times by 50 minutes for middle school students (pushing the start time from 8 AM to 8:50 AM) and 70 minutes for high school students (7:10 AM to 8:20 AM).

“Healthy school start times (8:30 or later for middle and high school students) is critical to help students obtain sufficient sleep, which is essential for all aspects of health, well-being, and learning,” the study’s principal investigator Lisa J. Meltzer, PhD, a pediatric psychologist at National Jewish Health, told Healthline in an email.

“Sufficient sleep is related to better mood, improved cognitive function, and better academic outcomes,” she added.

Participating students completed online surveys, answering questions about bedtime, wake time, total sleep hours, sleepiness while doing homework, and academic engagement.

Researchers found that the benefits of starting school later were manifold:

  • Both middle school and high school students slept for longer. High school students gained nearly an extra hour of sleep.
  • Both groups overslept less on the weekends.
  • Fewer students reported feeling too sleepy to do their homework.
  • Scores for academic engagement were also “significantly higher” for both groups.

“This study adds to a growing body of research that really has reached the same conclusions: that moving the start times back results in longer sleep cycles for adolescents,” said Dr. David Fagan, vice chair of pediatrics at Cohen Children’s Medical Center, New Hyde Park, New York.

Fagan was not affiliated with the research.

In recent years, other major public health organizations, including both the American Academy of Pediatrics and even the Centers for Disease Control and Prevention, have formally endorsed later school start times for middle school and high school.

The AAP wrote in a 2014 statement that the organization “strongly supports the efforts of school districts to optimize sleep in students and urges high schools and middle schools to aim for start times that allow students the opportunity to achieve optimal levels of sleep.”

The AAP recommends 8.5 to 9.5 hours of sleep for adolescents.

One year later, the CDC presented its own findings on the subject. Of primary importance: Schools starting at 8:30 AM or later give adolescents more opportunity to achieve appropriate sleep.

Nonetheless, they reported that the vast majority of schools, 75 to 100 percent across 42 states, started before 8:30 AM.

Insufficient sleep in teenagers is associated not just with worse academic performance but also other health issues including obesity, depression and anxiety, and increased likelihood of risky behavior and drug use.

Researchers have called the adolescent years a “perfect storm” for sleep problems, during which biological, psychological, and social factors make it difficult to get a proper night’s rest.

One of the major factors: a changing sleep schedule that makes them more wakeful later in the evening.

“We do know that as children enter puberty, there is a delay in when melatonin gets released. Melatonin is what impacts our ability to get to sleep… Preteens are morning people and then when you get to teens, you’re more of an evening person. That shift with the melatonin can result in over two hours of a change in sleep wave cycles,” said Fagan.

And while there are things parents and adolescents can do to help improve sleep quality in general, it’s increasingly clear that starting such changes with schools themselves could have a dramatic effect on health, achievement, and quality of life.

“I definitely believe that changing the start time for middle school and high school students is a step in the right direction,” said Fagan.