California high school and middle school students can enjoy extra rest on weekday mornings, starting this fall. A first-of-its kind law that just took effect says public high school classes can't begin earlier than 8:30 a.m. and middle schools must wait at least until 8 a.m. to start, except in rural areas. It's a response to medical studies about adolescent sleep needs, as well as comments by parents and students. New York and New Jersey are among states considering similar legislation.

Before the coronavirus pandemic, the average U.S. public high school start time was 8 a.m. Experts link chronic sleep deprivation among teens to reduced academic performance and mental and physical health problems, as well as substance abuse and drowsy driving. "When you give them the gift of increased sleep time, it is the biggest bang for the buck that you can think about," says Dr. Sumit Bhargava, a pediatrics professor at Stanford University in Northern California.

Seattle, Denver and other individual school systems acted earlier. The Camas School District in Washington State changed the start time for its three high schools from 7:40 a.m. to 8:45 a.m. in 2018 "to create the best possible conditions for our students to learn." Lisa L. Lewis, who advocated for California's law and wrote a 2022 book called "The Sleep-Deprived Teen," says starting school later "is a public health issue." A major medical group, the American Academy of Pediatrics, used the same words in a 2014 recommendation:
"Insufficient sleep in adolescents as an important public health issue that significantly affects the health and safety, as well as the academic success, of our nation's middle and high school students. . . . The evidence strongly implicates earlier school start times before 8:30 a.m. as a key modifiable contributor to insufficient sleep . . . in this population. Furthermore, a substantial body of research has now demonstrated that delaying school start times is an effective countermeasure to chronic sleep loss and has a wide range of potential benefits to students with regard to physical and mental health, safety, and academic achievement."

Federal agency says: "Most American adolescents start school too early." – Centers for Disease Control and Prevention, June 2022

Researcher says: "Asking a teenager to be awake and trying to absorb information at 8:30 in the morning in some ways is like asking an adult to wake up at 4 o’clock in the morning." -- Matthew Walker, University of California-Berkeley brain science professor

Medical group says: "The American Academy of Pediatrics strongly supports the efforts of school districts to optimize sleep in students and urges high schools and middle schools to aim for start times that allow students the opportunity to achieve optimal levels of sleep (8.5–9.5 hours)." – Policy statement, 2014