California Teens Sleep More, Score Higher With Later Start

Teenagers across California are finally getting the sleep they need, and it's already showing up in their test scores and mental health.

A new study reveals that California's 2022 law requiring middle schools to start no earlier than 8 a.m. and high schools no earlier than 8:30 a.m. is delivering real results. The share of students sleeping at least eight hours per night jumped by 13%, meeting the minimum health experts recommend for adolescents.

The academic gains are just as impressive. Eighth graders showed measurable improvements in both math and English scores. Hispanic and economically disadvantaged students saw the biggest jumps, likely because they were already struggling most with sleep deprivation due to family and work responsibilities.

Mental health improvements were equally striking. Boys reported the largest reductions in sadness, hopelessness, and suicidal thoughts. Hispanic students saw the biggest drop in difficulties concentrating.

"The first step in addressing student mental health problems is to not create them in the first place," said Terra Ziporyn, executive director at Start Schools Later. "Systematically depriving an entire adolescent population of adequate sleep is a surefire way to hurt their mental health."

California remains the only state in the nation with a statewide mandate for later school start times. Researchers used teacher commute data to track the changes, comparing sleep and mental health before and after the law took effect in the 2022-2023 school year.

The Ripple Effect

The study confirms what sleep researchers have long suspected: when kids sleep better, everything else improves. Osea Giuntella, a University of Pittsburgh researcher who co-authored the study, found that even moderate increases in sleep led to significant gains across the board.

Some parents worried that later start times would complicate work schedules and push back sports. The study found those concerns were largely unfounded. After-school activities did shift slightly later, but the changes were marginal and not statistically significant.

The transition wasn't easy for everyone. Some districts found the switch "too hard and too expensive," especially when redesigning bus routes. San Francisco Unified partnered with university operations experts to create new schedules, ultimately saving $5 million while satisfying most families.

Advocates say the state could have done more to help districts manage the change. Built into the law was support from the state Department of Education, but many schools didn't get the guidance they needed to ease the transition and build community support.

Researchers say California's bold move has set a powerful precedent, treating adequate sleep as a public health necessity rather than a negotiable budget item.