A recent article by Press Democrat reporter Kerry Benefield (“Sonoma County students, educators debate later start to high school days,” Sept. 5) discussed the effect fatigue and 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. A student's circadian rhythms — biological clocks that regulate periods of sleepiness and wakefulness — regulate when a student has the highest ability to focus and absorb new material.
Interestingly, cognitive rhythms are about the same for preadolescents and adults, but for adolescents, a group most susceptible to disrupted sleep patterns, this cognitive rhythm occurs one hour later.
Most teachers are acutely aware that 8 a.m. to noon is a high learning period, when students' circadian rhythms are considered best for learning. However, the weakest time for learning potential is from noon to 4 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 rapid eye movement, or REM, sleep. Students should be allowed to experience six REM periods over the course of nine hours of sleep. Therefore, the adolescent would have to go to bed at 10 p.m. and get up at 7 a.m. to satisfy the need for six REM 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 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.