Sleep is essential for memory and learning. Imagine your brain is a town, and instead of nerve cells you have homes and businesses. And instead of the pathways between nerve cells, you have roads connecting all of these structures. When your mind is working out a solution to a problem, your brain is building many new connections everywhere. Some of these new pathways will be helpful, but others will prove not to be useful. They will lead to stop signs, one way roads, or a dead end. At night while we sleep, the brain gets rid of those unneeded pathways, keeping only the important new ones and puts resources into those main roads to make them stronger. It is a process called “synaptic pruning”, much like you would prune a garden to get rid of the old growth and make room for new, healthy vegetation.
This brain undergoes “remodeling” during sleep. The remodeling every night strengthens memory and the ability to problem-solve the following day. REM sleep is one stage of sleep that is critical for memory consolidation and learning. The majority of REM sleep is obtained during the last third of the night. Teenagers are often forced to wake up for school during this critical time due to early school start times. When they are allowed to sleep, their cognitive abilities improve.
This study examined the outcomes for 9,395 students at eight high schools across the U.S. that implemented later start times, from 8:00 a.m. to 8:55 a.m. The study found significant decreases in absences and tardiness, as well as greater academic benefits for schools with the latest start times. Students in schools with the latest starting times were found to have the greatest academic achievement gains. The students who slept eight or more hours each night were less likely to report symptoms of depression and fall asleep in class. Moreover, after the change to a later start time, risky behaviors such as cigarette, drug, and alcohol use were significantly less likely to occur, and the number of car crashes in the districts studied decreased by 13%. Included are recommendations for schools and districts considering changing their high school start times.
This paper uses data on all middle school students in Wake County, NC, from 1999 to 2006, which identified a link between daily start times and academic performance. Using variation in start times within schools over time, the effect is a two percentile point gain in math test scores – roughly fourteen percent of the black–white test score gap. Similar results were found for reading scores, also looking at the variation in start times across schools. The effect is stronger for students in the lower end of the distribution of test scores. Increased sleep was found to be a mechanism which affects test scores. Later start times compare favorably on issues of cost, as compared to other education interventions which result in similar test score gains.
Hysing M, Harvey AG, Linton SJ, Askeland KG, Sivertsen B. (2016). Sleep and academic performance in later adolescence: results from a large population-based study. Journal of Sleep Research 25(3):318–324.
This study assessed the association between sleep duration and sleep patterns and academic performance in 16-19 year-old adolescents in Norway using academic grades available in secure data-bases. The study first used a large population-based study conducted across the country in 2012. The youth@hordaland-survey surveyed 7798 adolescents aged 16-19 years (53.5% girls). The survey was then linked with objective outcome data on school performance. Self-reported sleep measures from the survey provided information on sleep duration, sleep efficiency, sleep deficit and bedtime differences between weekday and weekend. School performance [grade point average (GPA)] was obtained from school registries. Most sleep parameters were associated with increased risk for poor school performance. After adjusting for socio-demographic information, short sleep duration and sleep deficit were the sleep measures with the highest odds of poor GPA (lowest quartile). Weekday bedtime was associated significantly with GPA, with adolescents going to bed between 10-11 PM having the best GPA. Also, delayed sleep schedule during weekends was associated with poor academic performance. The associations were somewhat reduced after additional adjustment for non-attendance at school, but remained significant in the fully adjusted models. In conclusion, the demonstrated relationship between sleep problems and poor academic performance suggests that careful assessment of sleep is warranted when adolescents are underperforming at school.
Although the current published studies on sleep and school performance have limitations, the findings in this meta-analysis strongly point out that self-reported shortened total sleep time, erratic sleep/wake schedules, late bed and rise times, and poor sleep quality are negatively associated with academic performance for adolescents from middle school through the college years. The authors note the importance of these findings; however, certain caveats were noted. Although the studies included in this review used a variety of measures of both sleep and academic performance, future studies should use multiple sources of measurement within the same study, such as parent and teacher ratings, school record data, standardized test batteries, and sleep laboratory and/or measures of actual physical activity. Schools, parents, and pediatricians need to take an active role to consider sleep and sleep disorders in the context of academic grades, test scores, absenteeism, emotional difficulties, and other aspects of daytime functioning and adolescent development.
The studies reviewed in this article discuss the effects of sleep loss on higher cognitive functions, such as attention, memory, and problem-solving. Learning capacity and academic performance may seriously be affected by the lack of sleep necessary for children and adolescents. Increasing daytime sleepiness, as a consequence of poor sleep quality, can seriously impair students’ cognitive functioning and behavioral performance. An association between academic performance and sleep habits or daytime sleepiness levels has also been suggested by children’s sleep-breathing disorders or obesity. An improvement in neuro-cognitive functioning can achieved by adopting healthy sleep schedules, such as fixed bedtimes and waking times, fixed school starting times, and by limiting psycho-social and home and school pressures.