LOS ANGELES — The Los Angeles Unified School District begins classes on a virtual bell schedule Thursday, with a later-than-usual start time of 9 a.m. Before the pandemic, school started at 7:50 a.m. – a grueling deadline for teenagers in particular, many of whom had to wake up hours earlier to get to class on time.

“Los Angeles Unified considered a number of factors in setting the 9 a.m. start time,” according to a LAUSD spokesperson.

The district had been hearing from families that a later start would allow them to better prepare their children for online learning. But the decision was also based on a new law set to take effect statewide in 2022. Senate Bill 328 calls for a start time of no earlier than 8:30 a.m. for high schools and no earlier than 8 a.m. for middle schools. A number of L.A. Unifed schools have already been piloting later start times, the spokesperson said. 

Researchers have known for decades that teenagers are safer, healthier, and learn better when they get more sleep and start school later. Numerous studies have shown that in addition to getting better grades, they don’t fall asleep in class as much, their rate of drowsy driving accidents declines, they’re less likely to show signs of depression. Also, they have a much lower incidence of illegal and legal substance use, including caffeine and nicotine.

In 2014, The American Academy of Pediatrics recommended that middle schools and high schools start no earlier than 8:30 a.m. to allow students to get enough sleep.

“What’s been shown is that when schools start before 8 or 8:30 in the morning, kids are being forced out of sleep at a time in their sleep cycle when important things are happening. The last three hours of sleep is when you get most of your REM sleep, and that’s when the bulk of emotional regulation and memory consolidation takes place,” said Terra Ziporyn Snider, executive director and co-founder of Start School Later, the grassroots student health and education advocacy group that helped pass SB 328 in California. 

“As a pediatrician, 9 a.m. for middle schoolers and 9:30 for high schoolers is a really sleep-appropriate start time,” said Max Van Gilder, a New York City doctor who in May and June, on behalf of Start School Later, conducted a national survey of more than 700 middle- and high-school students about their sleep and study habits before and after COVID.

Not surprisingly, during the pandemic, without the need to get up and go to school at a set time, most teenagers went to sleep about a half-hour later than before COVID, Van Gilder said. Sixth graders went to sleep at a median time of 10 p.m., seventh and eighth graders at 11 p.m., ninth and tenth graders at midnight, and eleventh and twelfth graders at 12:30 a.m.

“That goes along with what we know about circadian rhythm and moving of the sleep time later with age, peaking at eleventh and twelfth grade,” Van Gilder said. 

More surprisingly is that without the need to wake up at a specific time, almost all of the teenagers in the survey woke up at 9 a.m. – giving middle schoolers nine hours of sleep and high schoolers eight hours. 

Before the pandemic, when they attended in-person classes at a school, middle schoolers were getting up by 6:30 a.m. and averaging six-and-a-half hours of sleep, and high schoolers were getting up by 6 a.m., netting them just five-and-a-half to six hours.

Going to school from home, “They were going to sleep later, waking up later, getting the recommended hours of sleep, and they weren’t feeling tired during the day,” Van Gilder said.

There are few silver linings to COVID, but with distance learning, and a later start time, LAUSD teenagers might finally get the amount of sleep they need.