sleep foundation
The National Sleep Foundation

Medically Reviewed by

The National Sleep Foundation

Written by

The National Sleep Foundation

A modest delay in school start time of only 30 minutes could significantly improve adolescent alertness, mood and health, according to a study conducted in a small private high school. Judy Owens, MD, a sleep expert with Hasbro Children’s Hospital, reports in the July issue of the Archives of Pediatric and Adolescent Medicine that, “…the results of this study add to the growing literature that supports the potential benefits of such an adjustment to better support adolescents’ sleep needs and circadian rhythm in order to improve the learning environment and their overall quality of life.” Inadequate sleep in adolescents, defined as less than nine hours per night, is a known problem and a major public health concern. Biological changes in adolescents can cause what is known as a “phase delay,” which calls for later sleep onset and wake times due to a shift in circadian rhythms. Owens and other pediatric sleep experts have been encouraging delayed school start times to address the concern. To prove the benefits of a delayed start time in doing so, Owens conducted a study at a small private high school in Rhode Island, which delayed their start time from 8 a.m. to 8:30 a.m. The optimal sleep amount for adolescents is nine to 9 ¼ hours per night, despite the shift in their preferred wake/sleep times. Owens, who is also an associate professor at The Warren Alpert Medical School Brown University says, “On a practical level, this means that the average adolescent has difficulty falling asleep before 11 p.m., so the ideal wake time is around 8 a.m.” She also notes, “In addition to these biological factors, adolescents are exposed to multiple environmental and lifestyle factors such as extracurricular activities, homework and after-school jobs, which can all significantly impact their sleep patterns. As a result of sleep loss during the week, adolescents often “sleep in” on the weekends, further contributing to a disruption of their circadian rhythm and decreased daytime alertness levels.” Owens comments further, “It’s not surprising that a large number of studies have now documented that the average adolescent is chronically sleep-deprived and pathologically sleepy.” The study found that there was a significant average increase in sleep duration on school nights of 45 minutes across all grades (nine to 12) after the change in the school start time. The self report showed drastic declines in the percent of students who felt they “rarely/never” got enough sleep (69 percent to 34 percent), and those reporting “never” being satisfied with their sleep (37 to 9 percent). The consequences of sleep deprivation are far-reaching: impairments in mood, attention and memory, behavior control and quality of life; lower academic performance and a decreased motivation to learn; and health-related effects including increased risk of weight-gain, lack of exercise and use of stimulants. Learn more about the benefits of delaying school start times.