If you are the parent of a teenager – or if you just remember your own adolescent years – you know how hard it can be to get a teen out of bed and ready for school in the morning. Many people view these difficult mornings as a sort of moral failing and fall back on the “lazy teenager” stereotype. However, the reality is that adolescent sleep timing is the result of biological changes, not personal choices. In 2014, The American Academy of Pediatrics officially recommended that all middle and high schools should start at 8:30 am or later. This recommendation is based on the negative effects of early waking on teenagers’ sleep, academic performance, and mental and physical health. However, this recommendation is still not being followed, with most schools in the US starting at 8 am. To address this major public health issue, we need to communicate the science of sleep and circadian rhythms.
I. Circadian Rhythms
Circadian rhythms are variations in the way that our bodies function across the 24h day. The most prominent circadian rhythm is that of the sleep/wake cycle: humans tend to sleep at night, not during the day. But the influence of the circadian system doesn’t stop at sleep. Each day your blood pressure, body temperature, metabolism, even your mood and your ability to solve problems have predictable fluctuations across the day. Although circadian rhythms are broadly similar across all humans, there are individual differences in the timing of these rhythmic variations. A person’s natural circadian timing is referred to as their chronotype. If you’ve ever referred to someone as a “night owl”, you were actually saying that they have a late chronotype.
During puberty, around the same time that adolescents start developing secondary sex characteristics, they also experience a shift to a later chronotype. Physical events, like the peak release of certain hormones, occur later in the day than they used to. When this happens, many teenagers will find it difficult or impossible to fall asleep at their previous bedtime. To further complicate the problem, teenagers require more sleep than adults. While most adults can maintain their health while sleeping 7-8h per night, most teenagers need 8-10h. Adolescents who have to wake up early for school are often sleep deprived. While this is a serious concern in itself, there are even more consequences of fighting biological timing.
II.Circadian Rhythm Disruption
When we do things at a time of day that isn’t compatible with our circadian rhythms, we may experience a state of circadian disruption. Circadian disruption is the reason that you feel miserable when you are jet-lagged, the timing of external events no longer aligns with what your biological clock was predicting. Your brain will sense that the timing of the light in your environment has changed, and over a few days your circadian rhythms will shift, allowing you to feel better. However, we don’t have to take a flight to experience circadian disruption. Many people go to bed and wake up later on the weekend than they do on weekdays. This is actually a form of circadian disruption called “Social Jetlag”. Social Jetlag happens because there is a difference between a person’s chronotype and the sleep schedule that is mandated for them because of work or school.
Since Social Jetlag is so common, people often overlook it or think of it as harmless, but this is not the case. Circadian disruption increases the chances of developing metabolic syndrome, obesity, diabetes, and multiple forms of cancer. It affects the brain, increasing the rate of depression, anxiety, and ADHD, as well as leading to problems with working memory and sustained attention. Many people who study circadian rhythms, myself included, look at increasingly prevalent health problems like obesity, depression, and ADHD, and see a growing circadian crisis.
III. The Role of Science Communication
A hundred years ago, most schools started around 9 am. It was during the 1970’s and 80’s that many schools began to shift to an earlier schedule. Today, the average school start time in the US is 8 am. As early as the 1990’s, researchers and health professionals started to reach out to the public, saying that these early start times were harming children’s health. Although changing school start times may seem like a new and faddish issue, it’s actually been discussed in the scientific and educational communities for decades, although little progress has been made. I would like to bring attention to several areas of potential improvement in the communication around this topic, inspired in part by the article Science Communication Research: Bridging Theory and Practice.
One potential problem with communicating science around this topic is that it is always discussed alongside a specific policy recommendation: delaying school start times. Although this is a worthy goal, we may be undermining our own effectiveness. Research has shown that scientists lose credibility when they advocate for a preferred policy outcome. Some parents are hostile to the idea of delaying school because it will disrupt their morning routine, and therefore they may tune out information that is presented in that context. To communicate more effectively, we need to spark conversations about adolescent sleep and circadian health that are separated from the start time debate.
Another important aspect of science communication is engaging a diverse set of people to spread the message. Although public trust in science is high, scientists are generally not viewed as warm by the public, which can undermine trust. If scientists are the only people communicating this information, it is more likely that they will be perceived as pushing a biased agenda meant to help themselves rather than students. Teachers are likely to be the most important partners in this, as they have a close connection with students and parents. The involvement of healthcare workers, such as doctors and nurses, could also be very influential when it comes to discussing the health impacts of sleep and circadian problems. Politicians and opinion leaders of all kinds can also help bolster the trustworthiness of information.
Finally, past efforts may have been hindered by a lack of clear evidence for the benefits of delaying school start times. Previous research often depended on comparisons between adolescents in different parts of the world, or on animal models. Today, we have some better evidence to support the efficacy of delaying school start times. During the 2016-2017 school year, high schools in Seattle delayed their school start times by 55 minutes (from 7:50 to 8:45). Studies showed that students got 34 more minutes of sleep each night, and in one course their grades were increased by an impressive 4.5%.
For those who look at the current school system and say “if it’s not broken, don’t fix it,” let me be unequivocally clear: it is broken. The academic performance of American students continues to lag behind their peers across the world. Our academic competitors include countries that have later start times than we do in the US. In the UK, most schools begin between 8:45 and 9:00 am, while students in Finland start classes between 9:00 and 9:45 am. Although the US spends more on education per student than any other country except for Norway, our students continue to perform below the world average in mathematics. Beyond academics, American adolescents are struggling with their physical and mental health. Over 20% of the 10-19 year-olds in the US are obese, compared to just 10% in France. Perhaps the most sobering statistic is the increasing prevalence of depression among American adolescents. In 2005, 8.7% of adolescents had experienced a major depressive episode in the previous year. By 2014, it was 11.3%.
Of course, a change in school start times is not a magic bullet. The problems facing our nation’s adolescents are multifaceted, and our approach to helping them must be equally as varied. However, a change in school start times has an elegant simplicity that is lacking in many other interventions to improve the lives of adolescents. Re-designing class curricula, encouraging improved nutrition, and increasing mental health support are all important, but will likely require a lot of research, time, and money to implement. Delaying school start times is a relatively simple change, and one that we already have ample evidence to support.
The coronavirus pandemic has provided us with a unique opportunity to pause and reconsider the ways in which we organize our lives. While schools across the nation are shut down, I hope that adolescents are catching up on sleep. Adults, on the other hand, cannot afford to sleep on this opportunity. Now is an excellent time to reach out and start this conversation with students, parents, teachers, administrators, and other members of your community.
Start by educating yourself on the consequences of early school start times, using articles referenced here, and trustworthy resources like the Society for Research on Biological Rhythms. Share articles on social media platforms, or send them to parents, teachers, and school administrators. Many people may have heard about the push to change school start times — but they may not understand the reasons why it is so important. If you have a child or teen, talk to them about their experiences with their wake time, daytime sleepiness at school, and what they think about the matter. Help them learn to advocate for themselves through actions like joining the student government, writing petitions, and sending letters. Finally, whether you have school-aged children or not, consider reaching out to local officials such as school board members, and representatives in state and local government asking them to address this important issue. Together, we can build a plan that works for adults while protecting the health of adolescents.
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