NeuroVoices: Karin Johnson, MD, FAASM, on Advocating for Later School Start Times


The professor of neurology at UMass Chan School of Medicine provided perspective on the benefits of pushing back school start times based on what research has shown.

Karin Johnson, MD, FAASM

Karin Johnson, MD, FAASM

Insufficient sleep is common among children and adolescents, and is associated with several health risks including obesity, drinking alcohol, smoking tobacco, and using recreational drugs, as well as poor academic performance. A major reason for this lack of sleep stems from early school start times. In fact, a 2014 School Health Policies and Practices Study showed that 93% of high schools and 83% of middle schools in the US started before 8:30AM.

The American Academy of Sleep Medicine recommends that teenagers aged 13 to 18 years should regularly sleep 8 to 10 hours per day for good health; however, reaching this goal has become even more difficult. Over the years, accumulating research that has highlighted the benefits of pushing back school start times has led to change, as some school districts have begun to adopt a new schedule. Despite the increased efforts, most of the country still operates under the same start times. 

At the 2023 SLEEP Annual Meeting, held June 3-7, in Indianapolis, Indiana, Karin Johnson, MD, FAASM, chaired a session on sleep health advocacy, and the need for permanent Standard Time and later school start times. As part of a new iteration of NeuroVoices, Johnson, a professor of neurology at UMass Chan School of Medicine, discussed the benefits in later school start times, and the reasons why it should be a “no brainer” decision. Additionally, she provided context on some of the myths behind later school start times, and why there is no negative impact on social activities outside of school.

Is the sleep community all in agreement that school start time should be pushed back?

From the health, education, and economic side, as well as kids doing better in school, prevention from getting into car accidents, having depression and suicide, all of those things are better. Not only the sleep community, but the medical community, including the American Academy of Pediatrics, American Academy of Psychiatry, have supported later school start times as being the healthiest, safest approach. There are people that wonder: what will that do to busing? What will that do to sports activities? But what we've seen is that the communities—and now there's growing numbers who've been doing this over the last 10 years—have found that other than that scare of change, it can work out.

There are a couple of considerations. First, some new data has shown that if younger kids, elementary school kids, have to go to school earlier because of busing, that it doesn't impact their sleep. It is okay to flip them earlier in middle school and later in high school. You can still have that same busing scenario in different times but make it work. In terms of sports, they found that some teams do better despite shorter practice times because less kids are getting injuries, they’re more focused and get more done in their practices. Team can do better when they get more sleep. Last year, California changed to later school start times, but Florida voted on it as well. We're seeing these big changes statewide, which is really great. What we've seen before is that a lot of little communities did it, but some of the most at-risk people are those that live in cities and bigger places. Those are the ones that sort of often don't make the change unless there is that statewide approach.

How does the change from standard to daylight savings time impact children and adolescent sleep quality?

For context, we're on Standard Time in the winter, and in the spring, we switch to daylight savings time. Standard Time is more aligned with the sun, so the sun is more overhead at noon, whereas Daylight Saving Time is an hour later, and this causes a circadian misalignment. It also puts a squeeze on sleep, where people can't fall asleep until later and still must get up even an hour earlier. We're being tricked to go into work and school an hour earlier. All of that affects health.

This can have impacts in the short run. In the spring, that week or two after time change, we see more car accidents, more strokes, more heart attacks, and that's important. We want to end those. But what a lot of people don't realize is the long-term effects during the 8-month period on Daylight Saving Time. We may blame it on other things, but what we know is that those hour later sunrises and sunsets are associated with about a 10% increase rate of cancer, at least a 10% increase risk of obesity, and increased risk of heart disease. Those are even more important to get rid of than the sort of acute changes.

When we look at other issues, some people think that if it's lighter later, we'll get into less car accidents. That hasn't held up. Just because people drive more in the afternoon and you think light is protective against driving, we have to think about all the other factors that go into driving safety. This includes drowsy driving, drunk driving, distracted driving. Those things all increase when people don't sleep as well. There was a great study this past year by [Jeffrey] Gentry et al that showed that parts of the country that have more than a half hour later sunrise and sunset than have over a 20% increased risk of fatal car accidents.

There have been other data in education realm. Before 2007, Indiana had 3 different sort of time policies. The middle of the state was on set Standard Time, and the edges were either on Central or Eastern Daylight Saving Time. The research, which comprised over 10 years, compared the kids that were in these seasonal time changes versus the people on standard time. Kids on Daylight Saving Time kids had, on average, 16-point lower LSAT scores, but it wasn't felt evenly throughout the community. It was about 8 points lower if you were in the highest income [bracket], 23 points lower if you were in the middle income [bracket], and 49 points lower if you're in the lowest income. These effects aren't even across the population, as the most at risk groups were teenagers, and people with early work start time. If you're starting work, school, or caregiving activities before 8am, you're going to have your sleep more affected, and those people are going to get hurt more. We know that disproportionately falls on lower income workers, lower income families, as well as minorities. That's why we want these public health policies to help these vulnerable populations versus cherry picking groups that can sort of do what they want with sleep and get those benefits.

Transcript edited for clarity. Click here for more coverage of SLEEP 2023.

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