CNN: Changing middle and high school schedules can lead to significantly improved shut-eye for students, a new study found.

Researchers surveyed around 28,000 students in the Cherry Creek School District in Colorado over two years and found moving school start times later in the morning resulted in increased sleep times of around 45 minutes for students, according to research published Thursday in the journal Sleep.

Since many districts stagger their school buses in order to pick up everyone, the elementary school students began school an hour earlier over the course of the study so that older students could be picked up later, said study author Lisa Meltzer, a pediatric psychologist at National Jewish Health in Colorado. She said the research team found no significant difference in elementary school students’ sleep times after the hour change.

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