The reason? Researchers have found that - get this - teenagers are not at their best in the early-morning hours. Joke all you want, but teen drowsiness is a serious phenomenon, linked to such diverse ills as auto accidents and obesity. Sleep researchers say a key factor is a change in brain chemistry that starts with puberty - one that can't be addressed simply by telling the kid to hit the sack earlier.
Typical teens need 9 hours of sleep, but their bodies won't let them fall asleep much before 11 p.m. - a cycle regulated by later secretions of the hormone melatonin, said Judith A. Owens, lead author of a recent study in Archives of Pediatric & Adolescent Medicine.
Do the math: Teenagers need to sleep until 8 a.m., an hour when many schools are already in full swing. That means they're taking trigonometry with a brain at something less than full power.
Hoey, who is from Macungie, Lehigh County, said he always used to feel tired for the first few periods when the Hill School started at 7:55.
"You'd get out of it toward lunch," he recalled, in between bites of pancakes in the school's wood-paneled dining hall.
Now, after a schedule manipulation that required shaving off a few minutes here and there from activities throughout the day, he and other students say they feel more alert and productive. Visits to the school nurse went down, and grade-point averages even went up by two-tenths of a point, said Jennifer Lagor, assistant headmaster for student life.
And more of the private school's 495 students showed up at breakfast, where blue blazers are required attire. Among them is Hoey's roommate, Jae Woo Kim, who used to make up for missing breakfast by snacking later in the day. In a recent issue of the journal Sleep, scientists found that teens who sleep less than eight hours ate more fatty foods and snacks, raising the risk of obesity.
For the 20 percent of students who don't live on campus, the later start took some adjustment but is generally welcome, said sophomore Christina Bell, who travels each day from Honey Brook, Chester County.
"I like to do some studying in the morning," she said. "It was much more rushed with the other schedule."
Along with the morning delay came a change at the other end. The school made lights out half an hour earlier - at 10:30 p.m. - for freshmen, so teachers were encouraged to ease up on homework a bit.
Some staff members were initially doubtful. But Burton Merriam, director of the school's Center for the Arts, said the results were clear.
"It's amazing to me that half an hour would make that much difference," Merriam said. "I think we ought to make it even half an hour later."
Such changes have provoked resistance elsewhere, as school administrators are loath to interfere with busing schedules, sports, and after-school jobs. Schools in Kentucky and Rhode Island tried a later start only to switch back after schedule difficulties. In New Jersey, Glassboro superintendent Mark Silverstein said delaying the high school's 7:50 start time would depend on whether the bus schedule could be altered.
It is worth the effort, said Owens, associate professor of pediatrics at Brown University's Alpert Medical School.
Her study tracked a 30-minute delay in the start time at St. George's School in Newport, R.I., from 8 to 8:30, during the first few months of 2009. Students said they were more motivated and experienced fewer symptoms of depression. Attendance also improved, and despite waking up later, students also went to bed 18 minutes earlier, on average.
"I think they were more efficient students," said study coauthor Patricia Moss, assistant head for academic affairs at St. George's.
The teenage sleep cycle was first studied extensively in the 1990s, by Mary Carskadon, a colleague of Owens' at Brown. With the onset of puberty, boys and girls experienced a two-hour delay in their sleep cycles, she found. This was documented by when they became sleepy and, correspondingly, by when their bodies began to secrete melatonin, which was measured in saliva.
Yet despite this abrupt two-hour shift, the amount of sleep that teens need isn't much less than for younger children.
School districts in Minnesota were among the first to react by delaying start times, said Kyla Wahlstrom, director of the Center for Applied Research and Educational Improvement at the University of Minnesota in St. Paul.
Among the early results were lower dropout rates in Minneapolis, she said. It is less clear whether later start times lead to better grades, but the evidence points in that direction, Wahlstrom said.
It isn't all about biology, however.
Researchers say many teens make the problem worse by staying up much later than 11 p.m., wired to their smart phones and other electronic gadgetry. Or, in a competitive environment, such as the Hill School, they were staying up late to cram in more schoolwork, said Lagor, the assistant head.
"There is an element of personal responsibility on the part of the adolescent and the parent," said Brown University's Owens. "I don't want parents to feel like it's all biological stuff and let's just throw up our hands."
Late hours are even more pronounced on weekends, leading teens to try to compensate by sleeping in until noon, she said. No good.
Owens likens that to flying to Los Angeles and back every weekend - the equivalent of three hours of jet lag. And the rule of thumb is that it takes a day to catch up for every hour of jet lag, she said.
"It's going to take them until Tuesday or Wednesday to sort of get back to normal," Owens said. "They're sort of stuck in this crazy cycle."
At the schools with later start times, it's an open question whether the good sleep habits persist after graduation. Alex Hero, who pushed for the change at the Hill School last year as senior-class president, is now a freshman at Amherst College.
His first class meets at the leisurely hour of 11:30 a.m., he said in a telephone interview.
So what time does Hero go to bed?
"I don't know if I can disclose that," he said.
Contact staff writer Tom Avril
at 215-854-2430 or email@example.com.