Back to school - later? Sleep, school start times and academic performance
Does delaying school start times improve academic performance and mental health?
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Sleep, school starting times and academic performance
We all know good sleep is one of the main pillars of mental and physical health. Therefore, it is alarming to hear that a third of adults have trouble sleeping at any given time, elevating their risk of a whole spectrum of cardiometabolic, neurological and psychiatric disorders in the long term. But what if I told you that, according to the US Center for disease control and Prevention (CDC), up to 70% of adolescents sleep less than the recommended 8-10 hours on a given school day? Quite worrying, right? What’s more, short sleep at this age can increase the risk for obesity, diabetes, injuries, poor mental health, attention and behavior problems. But why do they sleep poorly and how does it reflect on their academic performance which can determine a significant part of their future professional life?
There are a couple of fundamental reasons for why teenagers sleep shorter than they should. Adolescents typically have a preference to stay active until late in the evening and to wake up late in the morning. During puberty, a period in life with many physiological changes, a teen’s sleep schedule also changes. The circadian rhythm, i.e. the body’s internal clock that controls the sleep/wake cycle, shifts a couple of hours later, thus making adolescents feel sleepy only later in the evening, around 10pm-12am. This completely natural shift is called sleep phase delay. Despite adolescents feeling sleepy later, they still need their 8-10 hours of nocturnal sleep. However, school in many countries around the world starts around 8am (or even 7am). Now it is easy to see why so many children, suddenly during adolescence, do not get enough sleep. Sometimes, they try to oversleep on the weekends which is also not great since the consistency of time of going to bed and waking up across the week is important for sleep quality. Needless to say that if teens go to bed late during the weekend, this “sleep debt” accumulates which significantly impedes their cognitive and academic performance in school.
During puberty, adolescents naturally experience a delay in their circadian rhythm, making them sleepier later.
Why does this delay in sleep even happen? Unfortunately, we’re not sure yet. One reason for this could be an apparent lengthening of the circadian period during the teenage years, which typically leads to a later onset of the biological night. Furthermore, some studies mention that the adolescent circadian clock is less sensitive to light during the morning when light usually advances the circadian clock and its timing of sleep. Finally, the homeostatic regulation of sleep, which increases sleep pressure with waking hours, could be altered in adolescents, leading to delayed sleepy feeling.
How does this shorter than optimal sleep affect adolescents’ academic performance? Without enough sleep, numerous studies have shown that children can have problems with attention, memory, problem-solving, and mood. Poor sleep can also contribute to emotional issues and behavior problems. All of this can significantly affect the child’s academic performance and overall wellbeing. One study showed that better quality, longer duration, and greater consistency of sleep correlated with better grades. Several other studies suggested that students with poor sleep get worse grades in various exams too. Not getting enough sleep increases daily sleepiness and the ability to learn which can naturally have an effect on grades.
How can we help teens get better sleep and academic performance? One way which has been shown to be very beneficial is slightly delaying school starts times – usually by 30-45minutes to at least 8:30am. A real-world study performed in The Seattle School District in the US delayed class times from 07:50 to 08:45 am and found that students got on average 34 min longer sleep duration, which was associated with a 4.5% increase in the median grades and an improvement in attendance. Delaying school start times also minimizes the difficulty of staying awake during lessons by reducing the levels of daytime sleepiness.
Many studies found a positive association between delayed school start times and academic performance.
Most cross-sectional and longitudinal studies reported an increase in total minutes of sleepfollowing later school start times, as well as improved academic performance too. One US study conducted on 9000 adolescents found that academic performance outcomes, including grades earned in core subject areas of math, English, science and social studies, plus performance on state and national achievement tests, attendance rates and reduced tardiness showed significantly positive improvement with the later start times of 8:35am or later. Furthermore, the same study evaluated several other factors. The number of car accidentsamong teen drivers was reduced by as much as 70% in the same study. On the other hand, teens getting less than eight hours of sleep reported significantly higher depressionsymptoms, greater use of caffeine, and are at greater risk for making poor choices for substance use.
Other positive effects of later school times confirmed by most studies which evaluated this were an increase in positive mood among students, increased class attendance and significant enhancement of attention levels during class, along with faster reaction timeand improved memory.
Overall, there is a strong scientific foundation connecting short sleep and poor academic performance. While it is difficult, or impossible, to stop the adolescents’ internal circadian clock getting delayed by approximately 2 hours in puberty, delaying school starting times to at least 8:30am seems like a much more feasible solution for most schools to accommodate for the natural sleep phase delay. While it will likely not make everybody get straight A’s in class, it is likely going to, at least slightly, improve performance by the virtue of feeling more rested, concentrated, in a better mood and less sleepy. And don’t forget, if the only impact of delaying school start times was on reducing the number of teen car accidents, I think it would be a no-brainer for every single parent around the globe.
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About the author
Alen Juginović is a medical doctor and postdoctoral researcher in the Department of Neurobiology at Harvard Medical School in Boston, MA, USA studying the effect of poor sleep quality on health. He is also organizing international award-winning projects such as Nobel Laureate conferences, international congresses, concerts and other, as well as participating in many events as a speaker. Feel free to contact him via LinkedIn or email for any inquiries.