Kids these days are getting less sleep than back when I was little. Surveys show that half of all adolescents sleep fewer than seven hours on weeknights. According to a University of Kentucky study, seniors in high school average slightly more than 6.5 hours of sleep per night. On average, school kids of all ages get about an hour less sleep than children were getting 30 years ago. Even kindergarteners average 30 minutes less shut-eye.

You might think, “Meh. A half hour, an hour. Is it that big a deal?”

Apparently…yes!

Using newly developed technological and statistical tools, sleep scientists have recently been able to isolate and measure the impact of this single lost hour. Because children’s brains are a work-in-progress until the age of 21, and because much of that work is done while a child is asleep, this lost hour appears to have an exponential impact on children that it simply doesn’t have on adults.

The surprise is how much sleep affects academic performance and emotional stability, as well as phenomena that we assumed to be entirely unrelated, such as the international obesity epidemic and the rise of Attention Deficit Hyperactivity Disorder. A few scientists theorize that sleep problems during formative years can cause permanent changes in a child’s brain structure: damage that one can’t sleep off like a hangover. It’s even possible that many of the hallmark characteristics of being a tweener and teen—moodiness, depression, and even binge eating—are actually symptoms of chronic sleep deprivation.

A researcher out of Tel Aviv University took 77 middle schoolers and divided them into two groups. Half were told to go to bed a half hour later for the next three nights, half to go to bed a half hour earlier. They wore wrist devices that measured sleep activity. After three days, a researcher measured the children’s neurobiological functioning.

The effect was indeed measurable—and sizable. The performance gap caused by an hour’s difference in sleep was bigger than the normal gap between a fourth-grader and a sixth-grader. Which is another way of saying that a slightly sleepy sixth-grader will perform in class like a mere fourth-grader. “A loss of one hour of sleep is equivalent to [the loss of] two years of cognitive maturation and development,” the researcher noted.

Another study found that sleep problems can cost a child a child up to seven IQ points, posing a threat similar to that of lead poisoning.

A University of Minnesota researcher surveyed 7,000 high school students about their sleep habits and grades.

Teens who received A’s averaged about fifteen more minutes sleep than the B students, who in turn averaged eleven more minutes than the C’s, and the C’s had ten more minutes than the D’s. Wahlstrom’s data was an almost perfect replication of results from an earlier study of more than 3,000 Rhode Island high schoolers by Brown’s Mary Carskadon. Certainly, these are averages, but the consistency of the two studies stands out. Every fifteen minutes counts.

And here’s the study that really made me pay attention:

Convinced by the mountain of studies, a handful of school districts around the nation are starting school later in the morning. The best known of these is in Edina, Minnesota, an affluent suburb of Minneapolis, where the high school start time was changed from 7:25 a.m. to 8:30. The results were startling. In the year preceding the time change, math and verbal SAT scores for the top 10 percent of Edina’s students averaged 1288. A year later, the top 10 percent averaged 1500, an increase that couldn’t be attributed to any other variable. “Truly flabbergasting,” said Brian O’Reilly, the College Board’s executive director for SAT Program Relations, on hearing the results.

Sleep deprivation is linked not only with poorer academic performance, but with impaired health overall, and may be a key factor in the rise in childhood obesity. Studies the world over have found that young children who get less than eight hours of sleep have a 300% higher rate of obesity than those who get ten hours.

Why are kids getting less sleep these days? The likely causes are overscheduling, homework, televisions and phones in kids’ bedrooms, lax bedtimes…and parental guilt. Working parents want to spend time with their kids, and that can mean bumping bedtime off just a bit.

Next up: Tips for helping kids sleep.

Posted by MommaSteph.