AURORA, Colo. — Students in the Cherry Creek School District went back to school on Monday. The superintendent says it is the third year since the district decided to push start times back for middle school and high school students.

“We’ve had students tear up, saying that this has changed their life,” Superintendent Scott Siegfried said. “Saying, ‘This allows me to get my work done, to be awake in class. First period is now an actual class, instead of something you try and get through with just coffee or soda.’ It’s changed their life.”

Siegfried says the district is taking part in a four-year study with National Jewish Health that is studying the impact of later start times; the study hopes to shed light on whether late start times could reduce depression, anxiety and even car crashes near schools.

Anecdotally, district leaders say they are seeing a difference.

“It’s the largest study throughout the nation that I know of that will really prove out that this matters. It’s the right thing to do for kids, to help them in school, to reduce depressive symptoms that reduce anxiety that reduce car accidents,” Siegfried said. “There are several things that we’re looking at that will really prove out that this was the right thing for kids.”

Cherry Creek middle schools’ start times were moved from 8 a.m. to 9 a.m. and high schools’ start times were moved from 7:10 a.m. to 8:20 a.m.

Siegfried says the elementary schools’ start times were shifted to an hour earlier, from 9 a.m. to 8 a.m.

“The earliest time at 8 a.m. still works very well for their body and their cycle. If you [know] elementary school students, they’re up early regardless. They still get a better learning cycle in earlier in the morning and they’re done earlier, so that day fits them well,” Siegfried said.

The study is expected to conclude in 2020.