An interview with Nerdy Guest Dr. Terra Ziporyn Snider
Q: Tell us a little about yourself and how you became interested in school start times.
A: As both a mother of 3 and a medical historian and writer (former associate editor at JAMA and co-author of The New Harvard Guide to Women’s Health), I’ve been living and breathing this issue on both a personal and professional front for decades. When my family moved to Anne Arundel County, Maryland in the year 2000, my oldest child was 12. We read in the newspaper that there was a pilot program to start one of the 12 county high schools at 9 a.m. the next year, based on science that was strong even back then. We were thrilled and relieved that by the time she went to high school, all county schools would start later. But the pilot program got cut at the last minute. All 3 of my kids graduated from a high school that started instruction at 7:17 a.m. And the daughter who started it all is now 34 with 3 kids of her own!
I almost gave up decades ago, just like so many other advocates and health experts before me. Working to make this change on a local level taught me some hard lessons about the nature of public health reform. I came to see that even when schools want to change, they often can’t: adult vested interests and myths often trump kids’ best interests. But everything changed when an online petition I whimsically started in fall 2011 connected me with people all over the country working on the same issue and facing the same obstacles. Re-energized, I co-founded a national coalition called Start School Later and to this day continue to serve as its Executive Director. Our successes. including California’s recently enacted “start school later” law, convince me that the time has finally arrived to resolve this frustrating and complicated issue—first because the research has become so compelling, and second because social media have reached a point where we can unite formerly isolated, short-lived efforts into a powerful network of advocates, researchers, health professionals, educators, and policymakers positioned to turn established sleep science into school policy.
Q: How is sleep beneficial for teens?
A: Sleep is beneficial—essential, in fact—for all human beings. It plays a key role in healthy growth, development, and virtually every aspect of functioning, including, for adolescents, cognition (e.g., attention and alertness, problem solving, learning, and decision-making); school performance (e.g., attendance and graduation rates, grades, test scores); mood (e.g., impulsivity, irritability, depression, anxiety, suicidal ideation); behavior (e.g., aggression and fighting, substance misuse, risky sexual behaviors and lifestyle choices); and mental and physical health and safety (e.g., driving safety, injury prevention and recovery, eating disorders and obesity, long-term risks of cardiovascular disease and multiple sclerosis),
Most teenagers need about 9 hours of sleep per night for optimal growth, development, and functioning, with individual variation ranging between 8-10 hours. But it’s not just the number of hours that matters. Sleep’s quality, timing, and regularity count, too. For teenagers, timing can be a particular challenge because of a reduction at puberty in the “homeostatic drive” to sleep”—i.e., the ability to resist the pressure to sleep that builds the longer you’re awake. Making matters worse, the body’s sleep-wake cycle temporarily shifts later at puberty, delaying the body clock (circadian rhythms) by 2-3 hours and making it hard for most teenagers—even the ones who bounced out of bed at dawn as toddlers—to fall asleep before about 11 p.m., or wake before about 8 a.m. (Scientists have found the same delayed cycle at puberty in animals, including rodents and primates—who presumably don’t have cell phones.) It doesn’t help that REM (rapid-eye movement) sleep—the stage believed to be critical for emotional regulation and memory consolidation—is concentrated in the last third of the night, i.e., in those early morning hour when we’re often forcing teens out of bed After a week of too little sleep, too many teenagers “sleep in” on weekends, creating a state of permanent “jet lag” (“social jet lag”), as if they flew coast-to-coast and back every single week.
Q: What are the major factors that impede sufficient sleep for teens?
A: Unless you’ve been sleeping under a rock, you’ve undoubtedly heard something about a “teen sleep deprivation epidemic.” Statistics vary from one study to the next, depending on how sleep deprivation is defined and measured, but clearly something is awry. The reports date back at least as far as a 2006 National Sleep Foundation poll showing that nearly 87% of U.S. high school students got well under 8 hours of nightly sleep, The Youth Risk Behavior Survey consistently shows that over 2/3 of US high school students get under 8 hours of sleep on school nights, with nearly 40% reporting an average of 6 or fewer hours. These findings worsen with every new survey. Other studies show that sleep loss increases as students progress through high school and that minority, urban, and students from lower socioeconomic status (SES) groups are most greatly affected.
Many potential “culprits” for this epidemic have been named, ranging from biologic changes at puberty to social forces, systemic challenges, and individual behaviors and sleep disorders. Some of these factors are hard if not impossible to address, starting with adolescent biology and including cultural forces such as a general de-valuing of sleep and electric lights extending natural daylight in our homes. Other factors—including overuse of electronics, social media, and caffeine—have been implicated, but the feasibility of addressing them effectively, particularly across an entire population, remains unproven. Still other factors, including late-night sports and play practices and midnight homework deadlines, may also contribute, although, again, rigorous studies about their contribution or effective ways to address them remain lacking.
The only factor that has been shown to play both a major and remediable role on a population level is early school start times. The problem here is not just that teenagers are not getting healthy sleep. The problem is that with current school hours, most teenagers cannot get healthy sleep. Many U.S. middle and high schools today start class in the 7 a.m. hour, with bus pick-ups beginning as early as 5:23 a.m. and wake-up and commute times even earlier. Nearly 10% start before 7:30 a.m., and about 43% start before 8 a.m., the average time U.S. high schools start. Students are waking as early as 4:30 or 5 a.m. to make it to class on time. So now the problem is clear. If teens aren’t falling asleep until 11 or 12 or even later – and we know that they are not – then waking at these hours is going to rob them of enough sleep, as well as that critical REM sleep. And they have no choice but to do it in most U.S. schools: a teenager who has to wake at 6 a.m. has to be sound asleep at about 9 every school night to get the recommended hours—and that’s usually not realistic for either social or biological reasons.
Q: What’s the evidence that high school start times should start at 8:30 am or later?
A: A large, broad, and consistent body of research shows that delaying high school bell times is a discrete, achievable fix affecting a large proportion of teenagers, leading the American Academy of Pediatrics, American Medical Association, Centers for Disease Control and Prevention, American Academy of Sleep Medicine, National Sleep Foundation, and many other major health organizations to recommend that middle and high school classes start no earlier than 8:30 a.m. Compelling empirical evidence shows that requiring teenagers to get up and off to class before about 8:30 a.m. interferes with school performance, impairing memory, attention, and judgment, and increasing truancy, absenteeism, tardiness, and drop-out rates. In addition, sending children to bus stops at 5 or 6 a.m. or putting young drivers on the roads when they are sleep-deprived endangers the whole community. And dismissing teenagers—especially sleep-deprived teenagers—from school in the early afternoon and leaving them unsupervised for 3 or 4 hours predisposes them to health-risk behaviors such as use of cigarettes, marijuana, alcohol, and stimulants; early sexual activity; depression and suicidal thoughts; and physical fights. Law enforcement data show that juvenile crime peaks in the unsupervised after-school hours.
Abundant evidence also confirms that when schools move bell times later, more students get more sleep. Several cross-sectional studies document a direct linear association between school start time and sleep duration, as does data from a wide variety of schools showing that when schools delay start times a greater proportion of students get more sleep and have more regular sleep-wake schedules. Other studies show a dose-response relationship between sleep and school start time, with 8:30 a.m. class times the watershed mark at which half to two-thirds of all students get at least 8 hours of sleep. In addition, both cross-sectional and outcome studies have consistently associated later school start times with fewer signs of depression, less stimulant and illegal substance use, and lower car crash rates, as well as with significant improvements in attendance, truancy, tardiness, suspensions, and graduation rates. Based on the car crash and graduation rate impact alone, The RAND Corporation projects that starting middle and high school classes no earlier than 8:30 a.m. would contribute $83 billion to the U.S. economy after just 2 years, and $140 billion after 15 years, with an average annual gain of about $9.3 billion and benefits far outweighing any immediate costs of change.
Q: Tell us a little bit about the new legislation in CA and what you see for the rest of the US?
A: Over 80% of US middle and high schools still start before 8:30 a.m. How can this be when the evidence for starting school later is so compelling? The explanation isn’t science, which is crystal clear. The explanation is politics. Community life revolves around school hours, so when you propose changing them, fear and speculation about how that change will affect already challenging daily schedules often override what evidence suggests is best for kids. The good news is that we have overwhelming empirical evidence that when schools change hours—which they often do, in both directions, for all kinds of reasons—community life inevitably adjusts. But fear and speculation (aka fear of change), coupled with widespread ignorance about sleep, are often more politically powerful than empirical evidence. The underlying problem is that sleep and school hours are fundamentally matters of public health, not education. But because our society still doesn’t view sleep as a basic human need, we have put a public-health decision into the hands of local school officials. That turns sleep-friendly school hours into negotiable budget items rather than non-negotiable public goods like clean air and water.
That is why California’s legislation establishing a floor on how early middle and high schools can require attendance (8:30 a.m. for high schools, 8 a.m. for middle schools) is a game changer. Co-sponsored by Start School Later and California State PTA, this groundbreaking law, which took effect July 1, is the product of many years of effort by a network of parents, students, sleep researchers, health practitioners, and educators withstanding considerable opposition from paid and powerful lobbyists. By setting statewide parameters for start times (much like statewide parameters for the number of days or hours children must be in class), it empowers local communities to overcome the myths and fear that have blocked evidence-based change for decades, positioning local districts to implement schedules that work for their communities while ensuring that teenagers have a chance to get a healthy night’s sleep. This approach to a seemingly intractable public health problem has understandably captured international media attention and sparked efforts to pass similar “child protection” legislation in other US states, including New York and New Jersey.