Teens sleep longer, are more alert for homework when school starts later

Middle and high schoolers felt less sleepy and more engaged in academics

June 7, 2019

Science Daily/American Academy of Sleep Medicine

Preliminary findings from a new study of middle school and high school students suggest that they got more sleep and were less likely to feel too sleepy to do homework after their district changed to later school start times.

In fall 2017, the Cherry Creek School District in Greenwood Village, Colorado, delayed school start times for middle school by 50 minutes (changing from 8 a.m. to 8:50 a.m.) and for high school by 70 minutes (changing from 7:10 a.m. to 8:20 a.m.). Results show that one year after the change, self-reported sleep on school nights was 31 minutes longer among middle school students and 48 minutes longer among high school students.

"Biological changes in the circadian rhythm, or internal clock, during puberty prevents teens from falling asleep early enough to get sufficient sleep when faced with early school start times," said principal investigator Lisa J. Meltzer, Ph.D., an associate professor of pediatrics at National Jewish Health in Denver, Colorado. "This study provides additional support that delaying middle and high school start times results in increased sleep duration for adolescents due to later wake times."

The American Academy of Sleep Medicine recommends that middle schools and high schools should start at 8:30 a.m. or later to support teen health, alertness and safety. However, a previous data analysis by the Centers for Disease Control and Prevention found that only 14% of high schools and 19% of middle schools started at 8:30 a.m. or later.

The study involved more than 15,000 students in grades 6-11 who completed online surveys during school hours before the start time change in spring 2017 (n=15,700) and after the start time change in spring 2018 (n=18,607). The survey included questions asking about weekday and weekend bedtime, wake time and total sleep time; sleepiness during homework; and academic engagement.

The study also found that the percentage of students who reported feeling too sleepy to do their homework declined after the school start time delay from 46% to 35% among middle school students and from 71% to 56% among high school students. Scores on a measure of academic engagement were significantly higher after the start time change for both middle school and high school students.

"The study findings are important because getting enough sleep is critical for adolescent development, physical health, mood, and academic success," said Meltzer.

CCSD Superintendent Dr. Scott Siegfried said that the study supports firsthand feedback he's received from students across the 108-square-mile district.

"I don't know how many of our high school students have come up to me and said, 'This has changed my life for the better.' They've told me they're getting up to an hour of additional sleep before school starts," Siegfried said. "That extra sleep makes a real difference in terms of health and wellness. The input from our students and the numbers from this landmark study point to the same conclusion: The change in our start times has been a positive step and benefited our students' everyday routines."

The research abstract was published recently in an online supplement of the journal Sleep and will be presented Wednesday, June 12, in San Antonio at SLEEP 2019, the 33rd annual meeting of the Associated Professional Sleep Societies LLC (APSS), which is a joint venture of the American Academy of Sleep Medicine and the Sleep Research Society.

Meltzer is also the senior author of another abstract from this study, "Impact of Changing School Start Times on Teachers/Staff," which found significant benefits of later school start times for middle and high school teachers and school-based staff. They reported increased sleep duration due to later wake times, as well as improvements in daytime functioning.

"This is the first large study to examine the impact of healthy school start times on teachers and staff," said Meltzer. "It is important to consider that this policy change, critical for the health and well-being of students, also impacts other members of the school community."

https://www.sciencedaily.com/releases/2019/06/190607113825.htm

Lack of sleep may increase likelihood of teens engaging in risky sexual behaviors

Majority of teens were not getting recommended amount of sleep, study finds

June 3, 2019

Science Daily/American Psychological Association

Teenagers who don't get enough sleep may be at an increased risk of engaging in unsafe sexual behaviors, such as not using condoms or having sex under the influence of alcohol or drugs, according to new research published by the American Psychological Association.

"Teens by and large are not getting the recommended eight to 10 hours of sleep a night, due to a number of reasons, including biological changes in circadian rhythms, early school start times, balancing school and extracurricular activities and peer social pressures" said Wendy M. Troxel, PhD, a RAND Corporation senior behavioral and social scientist and lead author of the study published in the journal Health Psychology. "Insufficient sleep may increase the potential for sexual risk-taking by compromising decision-making and influencing impulsivity."

Troxel and her co-authors, all from RAND Corporation, a nonprofit, nonpartisan research institution, analyzed data from a large, long-term study of 1,850 racially and ethnically diverse adolescents and young adults in Southern California. The data were collected four times between 2013 and 2017. Participants were, on average, 16 years old in 2013 and 19 years old in 2017.

The teens reported their sleep schedules on weekdays and weekends and whether they had trouble sleeping in the four weeks prior to filling out the survey. The participants also reported whether they used alcohol, marijuana or other drugs right before or during sexual activity and whether they used condoms.

The teens were grouped based on their sleep patterns over the four-year period, including weekday sleep duration, weekend sleep duration, differences in sleep patterns between weekdays and weekends, and sleep quality.

The majority of teens were classified as intermediate weekday sleepers, who got an average of 7.5 hours of sleep per school night, which is below the recommended sleep duration for this age group. There was also a group of teens, called short weekday sleepers, who got well below the recommended sleep duration, with 6.35 hours per school night. Only 26% of teens could be classified as sufficient weekday sleepers, averaging about 8.5 hours per night, according to Troxel.

As for the weekends, most teens in the study were intermediate weekend sleepers, clocking in just over nine hours, while long weekend sleepers netted an average of 10.6 hours and short weekend sleepers got an average of 7.8 hours, said Troxel.

Previous research has shown that irregular sleep patterns (e.g., sleeping in on weekends) can put teens at risk for negative health outcomes. Therefore, Troxel and her colleagues expected that teens who slept in on the weekends to make up for lost sleep during the week would show greater sexual risk-taking than those who had a more consistent sleeping routine.

Contrary to what they predicted, the researchers found that adolescents who were short weekday and short weekend sleepers (i.e., those who consistently did not get enough sleep) were nearly two times more likely to engage in unsafe sex than those who slept in, on average, an extra 3.5 hours on weekends.

"Teens who were short weekday and short weekend sleepers were not getting adequate sleep during the school week and were not catching up on sleep on the weekends, and thus were chronically sleep-deprived," said Troxel.

The researchers did not find that sleep quality had any effect on risky sexual behavior.

While this study could not make a direct link between sleep quality and sexual behaviors, it adds to a growing body of research about the potential role of sleep disturbances and adolescent risk-taking behaviors, Troxel said.

"Sexual risk-taking in adolescence poses serious health concerns, such as an increased potential of getting sexually transmitted infections, including HIV," she said.

Troxel acknowledged that the findings pose a significant challenge for parents, clinicians and policymakers.

"On one hand, we should encourage sleep routines for teens because regularity is important for maintaining healthy sleep and circadian rhythms," she said. "However, for most U.S. teens, whose weekday sleep opportunities are constrained due to early school start times, maintaining consistency in sleep-wake schedules throughout the week may not only be unrealistic, but also may be unhealthy, if it perpetuates a pattern of chronic sleep deprivation."

Troxel suggested possible strategies that may help teens get the sleep their bodies need.

"Our recommendation is for parents and teens to find a middle ground, which allows for some weekend catch-up sleep, while maintaining some level of consistency in sleep-wake patterns," she said. "We also need to encourage school districts to consider delaying school start times because this could make a substantial difference in helping teens get adequate sleep."

https://www.sciencedaily.com/releases/2019/06/190603102600.htm