Nikki is supposed to be working on a lab experiment in her chemistry class. Instead, she is slumped in her seat, twirling a piece of hair, and staring at nothing in particular as she yawns loudly and says, "I'm sooooo tired!" Take a stroll through an average school and you will see students in many classes yawning, "spacing out," or dozing with their heads on their desks. Some students fall asleep before the morning announcements are over. Such sleepy students can be found in any elementary, middle, or high school.
Do some of your students appear sleepy, spacey, or groggy? Do they misbehave or have lower-than-expected achievement? It is common knowledge among parents that when toddlers are irritable, unreasonable, hyper, and unfocused, it must be nap time. Although K–12 students may have outgrown nap time, their achievement and behavior are affected by lack of sleep.
To see how this works, consider the story of one student, as told by Dahl and Lewin (2002). Jay, a 10th grader, routinely stayed up until 3 a.m. and woke up at noon during the summer. When the school year began, he tried to go to bed at 10 p.m. but couldn't fall asleep until 3 a.m. He got up at 6 a.m. for school the first week but was exhausted. When the weekend came, he stayed up late and slept most of the day on Saturday to "catch up." He continued this pattern for several weeks. Sometimes he would oversleep and miss class, or he would fall asleep during class. His teachers and parents became angry, and Jay became irritable, had difficulty paying attention, and began failing his classes. This increased his anxiety, which made it harder for him to sleep. Eventually Jay was diagnosed with attention deficit/hyperactivity disorder and depression.
Many students, like Jay, are sleep deprived, and their sleep deprivation has significant implications for the classroom.
What Are the Results of Sleep Deprivation?
Sleep-deprived students tend to be more restless, irritable, and impulsive than other students (Bates, Viken, Alexander, Beyers, & Stockton, 2002). They also may be more depressed and have lower self-esteem than their classmates who sleep more (Fredriksen, Rhodes, Reddy, & Way, 2004). The effect can go in both directions—sleep deprivation may cause emotional disorders such as depression or anxiety, and emotional disorders may cause poor-quality sleep.
Another consequence of sleep deprivation is lower academic achievement. Poor sleepers are more likely to fail a grade than other students are, even when they do similar amounts of homework (Kahn et al., 1989). Third graders who have good sleep habits have higher grades in 5th grade than other students, after controlling statistically for earlier test scores (Buckhalt, El-Sheikh, Keller, & Kelly, 2009). Sleep deprivation decreases motivation, concentration, attention, and coherent reasoning. It decreases memory, self-control, and speed of thinking and increases the frequency of mistakes.
Note that students do not have to feel sleepy to experience these negative effects. People who are sleep deprived adapt; they may not report feeling sleepy even though their functioning has diminished (Beatty, 2001; Horowitz, Cade, Wolfe, & Czeisler, 2003).
Most of these studies are correlational, so you might wonder whether the positive outcomes linked to more sleep are really due to something else, such as healthy family routines. To test whether sleep causes these outcomes, researchers asked parents of students in grades 4 and 6 to put their children to bed earlier or later than usual for three nights in a row (Sadeh, Gruber, & Raviv, 2003). They found that students who went to bed an average of 30–40 minutes earlier improved in memory, motor speed, attention, and other abilities associated with math and reading test scores. Thus, even modest, temporary increases in sleep can have substantial effects on students' classroom functioning.
How Much Sleep Do Students Need?
As students grow, their need for sleep gradually diminishes. A good rule of thumb is "10 for 10"—10 hours of sleep for 10-year-olds. Younger children need more, and older children need less—except during puberty, when they typically need 9–10 hours. Adolescents who are growing rapidly or participating in sports may need even more sleep time.
Many U.S. students of all ages do not get enough sleep, but adolescents tend to be more sleep deprived than younger children. In fact, about 85 percent of adolescents are reported to be mildly sleep deprived, and 10–40 percent may be significantly sleep deprived (Dahl & Lewin, 2002).
Several changes in adolescence contribute to sleep deprivation. First, adolescents wake up more easily during the night than younger children (Carskadon & Dement, 2000). Second, adolescents stay up late for sports, homework, and jobs. Third, adolescents easily shift to a "night-owl" pattern. From ages 3 to 17, children tend to get up at the same time, about 7 a.m., but adolescents stay up about two and one-half hours later than younger children (Snell, Adam, & Duncan, 2007).
Adolescents often get less sleep on school nights and then sleep excessively on weekends (Ohayon, Carskadon, Guilleminault, & Vitiello, 2004). When they go to bed later on weekends than on school nights, they experience a "jet-lag" effect each week, and their school achievement may suffer. Research has shown that high school students who earn As orBs tend to have a small discrepancy between school-night and weekend bedtimes. In contrast, students with a discrepancy of two hours or more are more likely to earn lower grades (Wolfson & Carskadon, 1998).
Given the evidence above, improving students' sleep should be of great concern to educators. Indeed, it may be among the lowest-cost approaches to improving student learning.
What Can Schools Do?
The first thing schools can do is communicate with parents about the importance of sleep, including a consistent bedtime, even on weekends. When teachers notice signs that a student might be sleep deprived they should contact the student's parents. Parents can then stay in tune with their children's sleep needs by observing how easily they wake up in the morning. They can prevent sleep problems by eliminating conditions that disturb sleep—such as noise, stress, light, lack of exposure to daylight, and some medicines— and ensuring that children avoid large meals, exercise, TV viewing, computer use and caffeine consumption in the hour before bedtime (Roehrs & Roth, 2008). And they can enforce a consistent bedtime, with no more than two hours difference on weekends.
- Given the start time for most U.S. high schools, ensure that school activities such as basketball games or play practices end by 9 p.m. When traveling overnight with students for sporting events, science fairs, band competitions, or other school-sponsored activities, make sure students have a healthy bedtime. Some educators want to appear "cool" by encouraging late-night activities during such trips, but these activities undermine student achievement.
- Do not assign homework that requires staying up late. Give plenty of lead time for large projects. Convey to students that you would rather that they turn in homework late than pull an "all nighter." Be flexible about due dates so that students can juggle multiple commitments while getting adequate sleep.
- Advocate for a later start time for high schools. In one study, adolescents who transitioned from middle schools whose start time was 8:25 a.m. to a high school whose start time was 7:20 a.m. did not go to bed earlier (Carskadon, Wolfson, Acebo, Tzischinsky, & Seifer, 1998). As a result, they slept an hour less each night. In contrast, seven high schools in Minneapolis changed their start time from 7:15 a.m. to 8:40 a.m. Most students did not go to bed later, as some had feared, so they got 5 more hours of sleep per week (Wahlstrom, Davison, Choi, & Ross, 2001).
Changing the Cycle
Students with delayed sleep cycles, like Jay, can be gradually introduced to a healthier schedule by going to bed earlier in increments of 15–30 minutes over several weeks (Ollendick & Schroeder, 2003). Radical changes in sleep habits, as Jay attempted, are not as successful. For students with serious sleep problems, physicians or therapists might be enlisted to help with underlying medical, social, or emotional problems.
Parents and schools need to join forces to help students develop healthy sleep habits. If they do so, students' socioemotional well-being and academic achievement should improve, and educators' jobs should become easier.
