When Sleep Affects Learning Potential

           Kerry Benefield’s article titled Sonoma County Students, Educators Debate Later Start to High School Days (09/05/13) discusses the effect student fatigue and/or lack of sleep can have on a student’s learning potential. For example, according to brain scientists there are certain periods during the school day when students learn more efficiently than during other periods. A student’s circadian rhythms (daily biological clocks that regulate the timing of periods of sleepiness and wakefulness) define when a student has his highest ability to focus and absorb new material. Interestingly, cognitive rhythms are about the same for the preadolescents and for adults, but for adolescents, a group most susceptible to disrupted sleep patterns, this cognitive rhythm occurs one hour later.
           Most teachers are acutely aware of the 8 a.m. to 12 a.m. time block as a high learning period, when students’ circadian rhythms are considered best for learning. However, the weakest time for learning potential is from 12 p.m. to 4:00 p.m.  From 4 p.m. and later, student circadian rhythms regroup and move back to high points of learning potential
           Unfortunately, there is a Catch 22 to all of this, and that has to do with REM (rapid eye movements) or sleep. Students should be allowed to experience 6 REM periods over the course of a 9-hour sleep. Therefore, the adolescent would have to go to bed at 10:00 p.m. and get up at 7 a.m. to satisfy the need for 6 REM’s cycles. The selling point is that with each REM cycle, we have greater capacity for memory consolidation. In short, what your student learned during the day (working memory) has a greater chance of being encoded or stored into long-term memory during REM sleep cycles. Moreover, memory consolidation occurs more easily when the brain is not preoccupied with external stimuli, which occurs during REM sleep and which also supports your student’s circadian rhythms. This may explain why people who review important information before going to sleep are likely to remember that information the next day on a test.
           Our major dilemma? We cannot expect students to simply retire to bed early. According to medical researchers, the adolescents’ late sleep cycles are part of the maturation of the endocrine system. From the onset of puberty until late teen years, the brain chemical, melatonin, which is responsible for sleepiness, is secreted from about 11 p.m. until around 8 a.m., nine hours later! This secretion is based on human circadian rhythms and is fixed. In other words, typical students are not able to fall asleep much before 11 p.m. and their brains will remain in sleep mode until about 8 a.m., regardless of what time they go to bed. The Catch – 22 is that many high schools classes with early start times will cause students to rise earlier to get to school. Twenty percent of students sleep through the first two hours of school because their brains and/or bodies are still in the REM sleep mode. The loss of adequate sleep each night also results in a sleep debt for most teens. In extreme cases, the student may even develop a clinical disorder called delayed sleep phase disorder. Nevertheless, data from a research study in a major metropolitan public school showed that there was a significant reduction in school dropout rates, less depression and less drug use, accompanied by higher grades when they addressed students’ REM sleep and circadian rhythms.
           For starters we need to look more closely at academic classes that occur during the peak and down periods. The second suggestion is that schools, especially high schools, should start later to support both circadian rhythms and REM sleep patterns as demonstrated by scientific research studies.