Thousands of Maine high school students won’t be ready to learn when they return to class this fall, and it’s got nothing to do with the long summer break.

Instead, many of the teens will be too sleep-deprived to focus properly, the result of school start times that force adolescent students to wake up before their bodies and brains are ready to go for the day.

That disconnect affects mood, behavior, even safety. But more worrisome is that the lack of sleep may be holding back academic achievement, with enough evidence to suggest that schools should toss aside concerns of disrupting the school schedule and work to get teens to start the day later.

ASLEEP AT THE DESK

It’s not for nothing that teenagers are often portrayed as lethargic and indifferent, dragging a backpack down the hallway. Teachers have long known the difficulty of keeping the attention of adolescent students, particularly in morning classes.

Research backing that up has been building for years, and has now coalesced enough that the American Academy of Pediatrics advocated last week for pushing back the start of school, even if only for a half-hour.

The problem goes back to biology. Adolescents hitting puberty experience a hormonal change in sleeping patterns, one that tells them to stay up later. At the same time, they are entering the upper grades, which typically start earlier than elementary schools and often before 8 a.m.

That makes it difficult for the students to get the sleep they need – at least nine hours and as much as 10. According to a 2006 poll by the National Sleep Foundation, 87 percent of high school students do not get the recommended amount of sleep. In fact, on average, one study found, adolescents say they get less than eight hours of sleep per night.

Lack of sleep in students can lead to anxiety and depression. It causes some to have trouble controlling their emotions, and it can make students more likely to engage in risky behavior or get in a car accident on the way to school.

And while there isn’t as much evidence on the impact of sleep on academic outcomes, the research so far is compelling.

It shows that students who get more sleep are better able to concentrate during class and recall lessons later. They also finish assignments faster, in school and at home.

In addition, later school start times are associated with drops in absentee and tardy rates.

TIME SHIFTING

Now, school schedule changes don’t happen in a vacuum. A later start to the high school day affects the other schools in a district, as they typically share the same buses but at different times.

In fact, one reason that high schools start so early is that elementary schools prefer to start later, so young students don’t have to stand at morning bus stops in the dark.

And schools that start later also end later, affecting students who work or take part in extracurricular activities after school.

That juggling, and its associated costs, have kept schools from changing schedules on a large scale, despite the mounting evidence in favor.

Schools that have made the change, however, have found it can work, with some adjustments.

A high school in Hilton Head, S.C., for instance, is doubling its lunch period, from 25 to 50 minutes, to give students more in-school time to complete assignments. In Minneapolis, parents and other volunteers organized to watch over the elementary school bus stops in the early morning.

That’s not much to ask in exchange for happier, healthier, more attentive students.