Snooze or Lose: The Mismatch Between Sleep Patterns and School Timing

Imagine a typical high school student navigating a packed schedule of classes, homework, extracurriculars, a part-time job, and the ever-present pull of social media. Amidst all these demands, a full night’s rest often gets sacrificed. Losing out on sleep can have serious consequences for teens’ health and academic performance. According to the National Sleep Foundation’s 2024 Sleep in America poll, 8 out of 10 U.S. high school students get less than the recommended 8 to 10 hours of sleep. A growing body of research suggests that when and how consistently teens sleep may play a crucial role in their academic success.

In a study of nearly 800 adolescents, Gina Mathew and colleagues used wearable wrist devices to objectively measure students’ sleeping patterns over a week. These devices tracked bedtimes, wake times, and minutes of sleep. The researchers then compared these measures to the teens’ self-reported grades, school attendance, and disciplinary actions like suspensions.

[W]hen school starts early in the morning, teens are forced to wake up before their bodies are fully rested.

The study revealed that students whose sleep schedules were out of sync with their school start times—especially those who tended to fall asleep and wake up later—had significantly lower grades. Every hour of mismatch between a student’s natural sleep timing and the school schedule corresponded to a 7-8% decrease in their chances of earning straight A’s. This finding suggests that the root of the problem lies in the clash between teens’ biological clocks and early school start times.

During puberty, most teens’ internal clocks shift later, making them natural night owls. However, when school starts early in the morning, teens are forced to wake up before their bodies are fully rested. This mismatch between their natural sleep rhythms and externally imposed schedules, termed “social jet lag,” is what ultimately impairs academic performance, the researchers argue, rather than simply going to bed late.

Teens with inconsistent sleep schedules also faced more behavioral difficulties. The study found that the more a student’s bedtime varied from one night to the next, the more likely they were to face disciplinary action. In fact, for every hour that a teen’s nightly bedtime fluctuated, their chances of getting suspended or expelled increased by nearly a third. The researchers also found associations between inconsistent sleep schedules and greater difficulty focusing in class, maintaining good relationships, and completing assignments.

These findings align with the American Academy of Pediatrics’ recommendation that middle and high schools start no earlier than 8:30 AM. As of 2017-18, however, the average U.S. public high school started at 8:00 AM, with many starting classes even earlier. This means a significant number of teens must start learning at times that clash with their natural sleep rhythms.

[P]romoting healthy adolescent sleep will require a societal shift in attitudes, recognizing sleep as a vital component of health and learning rather than a lazy luxury.

Delaying school start times could help teens and their families get more sleep. In a study by Lisa Meltzer and colleagues, parents reported their own sleep habits before and after their school district delayed start times for middle schools from 8:00-8:30 AM to 8:50 AM and high schools from 7:10 AM to 8:20 AM. After the change, parents of middle and high schoolers reported sleeping later and longer themselves. Even two years later, more of these parents were getting the recommended 7-plus hours of nightly sleep, and fewer high school parents felt chronically tired.

Despite such compelling findings, changing school schedules can face community resistance. In 2017, Boston Public Schools planned to move high school start times later, from 7:30 AM to 8:30 AM, while simultaneously shifting elementary schools to an earlier time slot. However, this proposal met fierce opposition from parents who argued the changes would disrupt childcare arrangements and family routines. Amid the public backlash, the district ultimately scaled back the plan.

In the absence of later start times, the researchers offer some advice for helping teens get the sleep they need. Parents should encourage consistent bedtimes and wake times, even on weekends, and limit nighttime tech use. Schools can help by avoiding early morning extracurriculars and assigning less homework that keeps students up late. Ultimately, the researchers argue that promoting healthy adolescent sleep will require a societal shift in attitudes, recognizing sleep as a vital component of health and learning rather than a lazy luxury.