In a move designed to improve students' sleep habits, classes at Lincolnshire's Stevenson High School will begin 25 minutes later starting next year.
The school day will begin at 8:30 a.m. starting in August 2016. It starts at 8:05 a.m. now.
The change comes as pediatric health experts and activists nationwide are campaigning for later school-day starts.
Experts have said school districts that have pushed back start times have seen an improvement in student performance. Later start times also have led to fewer car accidents involving teenagers in those communities, experts have reported.
The Stevenson High board approved the change Monday. The school board also voted to start the 2016-17 term earlier so first-semester exams can be administered before winter break.
Proponents of the later school-day start said they hope the 25-minute delay gives teens more time to sleep.
In a video message to the Stevenson community, Principal Troy Gobble cited an American Academy of Pediatrics study warning against starting school before 8:30 a.m.
Additionally, Gobble said a survey of Stevenson students indicated many don't go to bed until after 11 p.m. on school nights.
"So there are many students who are probably getting six hours of sleep or less per night," Gobble said. "That's about three to four hours less than what is recommended."
Starting the school day later also gives teachers more time to meet with their colleagues and with students, Gobble said.
Although classes will start later, the school day still will end at 3:25 p.m.
To accommodate the shorter day, class periods will have 47 minutes of instructional time, down from the current 50 minutes.
First-period classes will be 51 minutes long, but that includes four minutes of morning announcements.
Also, passing periods will shrink from 10 minutes to seven minutes.
Dr. Judith Owens, director of sleep medicine at the renowned Boston Children's Hospital, said sleep deprivation among teenagers is a major health issue in the U.S.
The co-author of the American Academy of Pediatrics' position statement on school start times, she called the Stevenson board's decision "wonderful."
Students who attend high schools that start later are tardy less often, report depression less often and complain about fatigue less often, Owens said.
"The evidence is so compelling," she said.
Northwest Suburban High School District 214, Barrington District 220, Elgin Area District U-46 and Naperville District 203 are among the suburban agencies that have studied delaying start times, but none have taken the step yet.
Nationally, schools in 43 states have pushed back start times or are planning to make that move, according to Start School Later, a national nonprofit group based in Maryland.
The other schedule change approved by Stevenson High's board this week moves up the start of the 2016-17 school year by three days, to Aug. 15, 2016. The last day of classes moves to May 25, 2017, with graduation scheduled for the next day.
Officials have debated changing the start of the school year for more than a decade.
Final exams for first-semester classes long have been administered in the second week after students return from winter break. Last school year, that was mid-January.
That means students are studying over winter break instead of enjoying vacation, officials said.
"Even if they go away, our students still have exams or homework hanging over their heads during the two-week break," Gobble said.
Having exams after winter break also means students aren't learning new material for about a month, he said.
Scheduling exams before winter break lets students immediately start second semester in early January, rather than spending a week or longer preparing for finals.
"By moving semester exams before winter break, we will allow students to have a true break," Gobble said. "A break without books, a break without final exams to look forward to, and time to spend with their families."
Stevenson isn't the only suburban high school to go for an earlier start to the school year. Maine Township High School District 207 did so this year, and Barrington High School made the shift last year.