The transition period between summer and school represents a key time for children and adolescents to focus on sleep, correct poor sleep habits, and set themselves up for long-term success, both academically and physically.
For children and adolescents, the importance of sleep cannot go understated. Existing literature has shown that poor sleep quality and/or quantity in children are associated with a host of problems, including academic, behavioral, developmental, and social difficulties, weight abnormalities, and other health problems.1
With the start of schools across the United States already occurring, the importance of sleep quality in this age group is intensified, as many will undergo major changes to their sleep regimen in a shortened period of time because of changes in daily schedules.
Typical recommendations have indicated that infants need a minimum of 12 hours of sleep, while the suggested amount is 11 hours for toddlers, 10 for preschoolers, 9 for school-aged children, and 8 for teenagers. Some sleep disorders that are common in children and adolescents can be related to particular behaviors, whereas others may be caused by neurological or other medical conditions. The most common sleep disorder is insomnia, followed by clock or timing disorders, which impact circadian function.2
Other types of sleep disorders include parasomnias, which are undesirable physical events or experiences that are common in younger children while they are falling asleep; during sleep or REM sleep; or during arousal from non-REM sleep. “They’re actually very common in children, and more common in children than adults, because they usually happen in your deepest stage of sleep. Children have more deep sleep than adults, so that’s why you see more of them. They have names like sleepwalking, confusional arousals, or sleep terrors. Those happen in your non-REM sleep,” Carol Rosen, MD, professor of pediatrics, Case Western Reserve University, told NeurologyLive®.
Other types of sleep disorders include movement disorders such as restless leg syndrome and periodic limb movement disorder, which cause sensations in the legs and an overwhelming urge to move them. Other children may have obstructive sleep apnea, which interferes with breathing during sleep, and may be more common in children who have enlarged tonsils or adenoids or in those who have structural problems of the face or head, such as a cleft lip and palate. Additionally, those with behavioral disorders—such as autism spectrum disorder and attention deficit hyperactivity disorder—or mental health problems—such as anxiety and mood disorders—often also have insomnia.
Poor sleep can have a major impact on several domains, one of which includes mood. "When you’re cranky, it affects emotional regulation," said Jodi Mindell, PhD. “How can you keep it together? Do you get angry much more easily? Do you burst out into tears? Do you start laughing and can’t control it? The kid whose super silly in school may be because they can’t regulate their emotions because they’re not getting enough sleep."
Mindell currently serves as psychologist in the Department of Child Adolescent Psychiatry and Behavioral Sciences, as well as the associate director of the Sleep Center at the Children’s Hospital of Philadelphia (CHOP). In addition to mood, she named cognition, behavior, health, and families, as the 5 main impacted domains of sleep-related issues in children and adolescents. In these age groups, the link between insufficient sleep and increased risk of obesity is well-established, although the reason for this link is still debated. This lack of sleep can lead to metabolic irregularities, skipping breakfast in the mornings, and increased intake of sweet, salty, fatty, and starchy foods.3
The effects of good sleep can be seen as early as prekindergarten (pre-K) and kindergarten stages. One recent study by Douglas Teti, PhD, of Penn State, showed that children who slept 10 or more hours per night, especially at pre-K, consistently predicted more favorable outcomes in kindergarten in socioemotional, learning engagement, and academic domains. Overall, establishing healthy nighttime sleep habits before kindergarten start was especially promotive of better adjustment to kindergarten across the full year.4
Throughout the summertime, the sleep schedule for children and adolescents becomes significantly altered. The opportunities to spend time with friends and family as the sun remains up is something all children cherish; however, it leaves them going to bed later and waking up significantly later. As school begins to creep up, parents will begin to try to get their child back on a more normal schedule.
"We’re going to need a transition time that will probably take 1 or 2 weeks," Rosen said. "It’s naturally easier for us to go west, sleep in, and stay up late. It’s not easy to go east, to fall asleep earlier, and get up earlier. That’s tough.” Rosen expressed that as the summer winds down, parents should take note of when their child needs to be up, and how many hours of sleep it takes for them to be optimally functioning.
"A lot of people go into the school year—with kids free running all summer long, staying up late—and decide that on the first Sunday night, it’s time to get to bed. It doesn’t work that way," Mindell said. "Here on the east coast, or at least in our area [of Philadelphia], most of our kids start after Labor Day, so it’s compounded by a long, holiday weekend. By then, they’ve really fallen apart."
Summer can have a profound impact on a child’s biological clock, which leaves them prone to circadian rhythm sleep disorders. Symptoms of these disorders include daytime sleepiness, difficulty falling asleep, difficulty staying asleep, excessive sleepiness, lack of daytime alertness, poor concentration, and sleep that is not restful. The most common pediatric circadian disorder is known as delayed sleep-wake phase syndrome, where children function normally on a delayed sleep schedule, but struggle on a more typical sleep schedule used during the school year.5
The use of the internet and the adoption of mobile devices like smartphones and tablets have vastly expanded over the past decade, and these technologies play a significant role in the everyday lives of American families. In March 2020, the Pew Research Center asked parents a series of questions about their children under the age of 12 years and how they engage with digital technologies. Among the 60% of parents who say their child interacts with a smartphone, 6-in-10 said their child began engaging with a smartphone before the age of 5 years, including roughly one-third who said their child began this before age 2, and 29% who said it started between ages 3 and 4. Results also showed that 17% of children younger than 11 have their own smartphone, and of these, one-third of parents (35%) said this happened between ages 5 and 8.6
"There’s no question that the plethora of screens is impacting everyone. Doesn’t matter whether you’re a 2-year-old, an 8-year-old, or a 40-year-old," Mindell said. "The screens are sort of ubiquitous. Everyone has them in the bedrooms and they’re using it at night. The concern that most people talk about with screens is the exposure to blue light. Blue light affects melatonin, suppresses it, and make it more difficult to fall asleep."
The blue light typically emitted from a mobile device is an artificial color that mimics daylight. Studies have shown that blue light emitted by smartphones is not only bad for vision but has negative consequences on sleep. Exposure to blue light can affect the internal body clock and throw off circadian rhythm, which is in tune with light and dark. Research has also found a correlation between suppressed levels of melatonin, a hormone responsible for controlling the sleep-wake cycle, and exposure to blue light. As a person’s body runs low on melatonin, they can experience insomnia, tiredness during the day, and irritability.7
Although assessed in more of an adolescent cohort, a 2020 research study concluded that using mobile screens for more than 8 hours a day and use of mobile devices for at least 30 minutes before sleeping after the lights have been turned off are positively associated with poor sleep quality. “Keeping the mobile near the pillow while sleeping" was also positively correlated with daytime sleepiness (P = .003), sleep disturbances (P = .004), and increased sleep latency (P = .001). These habits, oftentimes thought to be harmless, can have a significant impact on overall health.8
"It’s ubiquitous. I mean, there’s no putting the cat back into the bag, so to speak, because it’s all over the place, sort of speak,” said Clete Kushida, MD, PhD. “What parents can do at this point is be very judicious about how they limit their children. Some parents will want to limit the screen time by a number of hours per week, and some don’t even allow them to have screen time during parts of the week. Individually, it only becomes an issue if it starts to delay their sleep time or bedtime significantly.” Kushida currently serves as a neurologist, a professor in the Department of Psychiatry and Behavioral Sciences at Stanford University. Additionally, he is also the associate chair, division chief, and medical director of Stanford Sleep Medicine; and director of the Stanford Center for Human Sleep Research.
"The good news is there is so much learning and positivity about electronics, but electronics and bedtime can be a big problem for children because they’re so exciting and can override [sleep]," Rosen told NeurologyLive®. "A lot of parents feel like, ‘Wow, I’m doing the best for my kid. I got them their iPhone or iPad. They can now learn in their bedroom.’ But, they are so desirable for children. They might be winding down and they’ll get a second wind with those exciting videos."
In addition to the recent efforts to eliminate daylight savings, many across the country, including those who treat pediatric sleep disorders, believe school start times should be pushed back as well to allow children to benefit from extra sleep time—and there is evidence to support this decision. In 2020, a study examined the association between a 50-minute delay (7:20 AM to 8:10 AM) in high school start times in Fairfax County, Virginia, and changes in rates of adolescent motor vehicle crashes.9
All told, the crash rate in 16- to 18-year-old licensed drivers in the earlier start times was significantly higher, with 31.63 accidents per 1000 for earlier times vs 29.59 accidents per 1000 for later start times (odds ratio [OR], 1.07; 95% CI, 1.0-1.4; P = .03). Additionally, regarding subtypes of crashes, there was a trend toward significance in distraction-related crashes per 1000 between the start times.
One 2017 study looked at delayed high school start times later than 8:30 AM and their impact on graduation rates and attendance rates. The analysis included 29 high schools with more than 30,000 students across 7 states. Findings showed that 2 years after a delayed start was implemented, average attendance rates and graduation rates increased several percentage points. For example, the average graduation completion rate was 79% before the delayed start was implemented vs 88% afterward.10
"Moving high school start times to a later time is a no-brainer," Mindell said. "We want our kids learning in school, and that has to align with when their brains are awake. High school start times are insanely early, and, in many cases, much earlier now than they were 30 or 40 years ago. All the research, too. I mean, there’s study after study showing attendance rates, dropout rates, academic functioning, drowsy driving care accidents. In every way, kids benefit from it."
These changes have been explored in some areas, at least in brief, despite the logistic challenges associated with them. Where Mindell works, in Philadelphia, it appeared at first that changes might be made to these schedules, when in early July 2022, the School District of Philadelphia announced that it planned to shift classroom schedules at 51 of the high schools from a 7:30 AM first bell to a 9:00 AM start time, beginning with the 2022/23 school year. Although, just a few weeks later, the district backtracked on its decision, citing the need for stability and a shortage of bus drivers.11
"Whenever there’s a change from the status quo it can always cause problems," said Kushida. “Some of the pushback has been from how schools are set up, in terms of staffing, which is understandable. But the broad picture is that it does create an impact on children because the sleep requirements are noticeably different from that."
Experts like Kushida have expressed a need to at the very least, stress the importance of sleep early on in life to establish consistent behaviors for the future. But, even with the associated difficulties, the literature is supportive of a change to school start times and schedules to better support sleep, and of the commonality of these disorders among children. "It’s important to make sure that your children are allowed adequate amounts of sleep and because their circadian rhythms already have a natural tendency to want to sleep late and get up later. To be able to accommodate late awakening time is very important," Kushida said.