Sleep is crucial for healthy brain development and overall physical and emotional health. When you sleep, your brain strengthens the neural pathways that synthesize the information you learned that day. According to the National Sleep Foundation (NSF), not getting enough sleep can limit academic success, lead to aggressive behavior, cause one to eat unhealthy foods, intensify the effects of alcohol, increase the use of caffeine and nicotine, lead to drowsy driving and contribute to illness. Not surprisingly, lack of sleep is correlated to depression. According to NSF’s 2006 Sleep in America poll, “manyadolescents exhibit symptoms of a depressive mood on a frequent if not daily basis, and these teens are more likely to have sleep problems.” The NSF reports that teens should get 8 to 10 hours of sleep every night. However, with extreme homework loads, after school activities, jobs and other tasks, 85 percent of teens don’t get the recommended amount of sleep. Jerusha Conner, an associate professor of education at Villanova University, researched the amount of sleep that students got at some schools across the country. Students from her sample reported sleeping an average of only 6.8 hours. In some schools, that average falls as low as six hours on weeknights.
During adolescence, biological sleep patterns shift to later at night. In other words, it is a natural tendency of teenagers to stay up later and wake up later in the morning. Dr. Mary A. Carskadon of Brown University found that older teens had later circadian rhythm timing based on melatonin secretions in saliva samples. In adolescence, the melatonin secretion occurs at a later time, which makes it difficult for teens to fall asleep earlier in the evening. The melatonin secretion also turns off in the morning, which explains why it is harder for teens to wake up early.
Given the fact that there is a biologically-dictated shift in sleep for teens, it seems like common sense for middle and high schools to start later in the morning. The American Academy of Pediatrics recommends that schools start no earlier than 8:30 a.m. However, the majority of high schools in the United States start before 8:30 a.m. and 43 percent start before 8 a.m. Carskadon explains, “Even without the pressure of biological changes, if we combine an early school starting time– say 7:30 a.m., which, with a modest commute, makes 6:15 a.m. a viable rising time– with our knowledge that optimal sleep need is 9 and a quarter hours, we are asking that 16-year-olds go to bed at 9 p.m. Rare is a teenager that will keep such a schedule…” It is unreasonable for school administrators to assume that teens will be able to get the recommended amount of sleep. The public seems to agree. According to the National Sleep Foundation’s 2002 Sleep in America poll, “80 percent of respondents said high schools should start no earlier than 8:00 a.m.each day… 47 percent said start times should be between 8:00 and 8:30 a.m.”
While some worry that starting school later will interfere with learning, the opposite appears to be true. The evidence indicates that, with later start times, teens are more academically successful, their behavior improves, and they have a healthier lifestyle. For example, Dr. Kyla Wahlstrom of the University of Minnesota investigated the impact of later start times on student performance after the Minneapolis Public School district changed the starting times of seven high schools from 7:15 a.m. to 8:40 a.m. The attendance rate, student alertness, and the enrollment rate improved, and there was less student- reported depression. In Edina, Minnesota, they changed the high school start times from 7:25 to 8:30 a.m. In the year before the time change, “math/verbal SAT scores for the top 10% of Edina’s 1,600 students averaged 683/605. A year later, the top 10% averaged 739/761.” Starting school an hour earlier was correlated with an improvement in student SAT scores by 56 points for math and 156 points for the verbal section.
On the flip side, Carskadon and researchers investigated what would happen to teenagers if the school starting time was changed from 8:25 to 7:20 am. They found that in the 10th grade, the average amount of sleep the students were getting dropped from 7 hours 9 minutes to 6 hours 50 minutes. Nearly half of the students showed a reversed sleep pattern that is similar to narcolepsy. Although the students who exemplified this pattern didn’t have narcolepsy, their circadian rhythms were significantly interrupted.
Although changing school start times is one solution for teens to get more sleep, it is not the only one. Carskadon says, “It’s important to add sleep to the curriculum at all grade levels and make sleep a positive priority.” This will help kids and teens to learn about the importance and necessity of sleep. Parents can also set boundaries around screen time. Students are often distracted by electronics while doing their homework. These interruptions can make students procrastinate, making homework take longer that it needs to. Lastly, teachers should work to assign a more manageable workload. This will ensure that students are not up all night working on tedious assignments.
Of course, there are challenges to pushing school start times back. Transportation, athletic programs, extracurricular activities, student employment, impact on families and other factors are a few things that need to be considered. But to ignore the reality of sleep deprivation among teens has serious repercussions as well. It is time for school administrators to pay closer attention to the research on the adolescent brain and the positive effects of later start times. Schools need to make sleep a priority.