Sustained benefits of delaying school start time on adolescent sleep and well-being

Epidemiology of sleep patterns and circadian typology in uruguayan children: The contribution of school shifts

Healthy sleep is defined by the combination of adequate duration, good quality, and regular timing. In children, sleep thus depends on the interplay of individual, parental, organizational, community, and social variables, but only a few studies have addressed this issue in a comprehensive way nationwide. Using the Uruguayan nationally representative survey (Nutrition, Child Development, and Health Survey, Encuesta de Nutrición, Desarrollo Infantil y Salud, ENDIS), we present the first epidemiological characterization of chronobiological and sleep parameters in Latin American children. On average, Uruguayan urban children (n = 2437; 5-10-years old) showed quite late chronotypes (MSFsc = 03:53 ± 1:07), moderate misalignment (SJL = 1.0 ± 0.9 h), and adequate sleep duration (SDweek = 9.9 ± 1.0 h). Further, we show the substantial influence of school shift schedules on children's circadian typology and sleep patterns. Our results show that children attending the morning school shift have a higher risk of sleep problems than afternoon-school shift ones. The chronotype and sleep were earlier in morning-school shift children than in children attending the afternoon school shift. However, morning-school shift children had stronger misalignment, shorter sleep on school days, and a higher risk of chronic sleep deficit and non-healthy circadian misalignment (even worse in late chronotypes) than afternoon-shift children. This evidence points to the need of evaluating policies to reorganize school start times to prevent the negative effects that early schooling seems to have on children's sleep health, which has been neglected so far.

Do later school start times improve adolescents' sleep and substance use? A quasi-experimental study

OBJECTIVE

A later school start time policy has been recommended as a solution to adolescents' sleep deprivation. We estimated the impacts of later school start times on adolescents' sleep and substance use by leveraging a quasi-experiment in which school start time was delayed in some regions in South Korea.

METHODS

A later school start time policy was implemented in 2014 and 2015, which delayed school start times by approximately 30-90 minutes. We applied difference-in-differences and event-study designs to longitudinal data on a nationally representative cohort of adolescents from 2010 to 2015, which annually tracked sleep and substance use of 1133 adolescents from grade 7 through grade 12.

RESULTS

The adoption of a later school start time policy was initially associated with a 19-minute increase in sleep duration (95% CI, 5.52 to 32.04), driven by a delayed wake time and consistent bedtime. The policy was also associated with statistically significant reductions in monthly smoking and drinking frequencies. However, approximately a year after implementation, the observed increase in sleep duration shrank to 7  minutes (95% CI, -12.60 to 25.86) and became statistically nonsignificant. Similarly, the observed reduction in smoking and drinking was attenuated a year after.

CONCLUSIONS

Our findings suggest that policies that increase sleep in adolescents may have positive effects on health behaviors, but additional efforts may be required to sustain positive impacts over time. Physicians and education and health policymakers should consider the long-term effects of later school start times on adolescent health and well-being.

Solar clock and school start time effects on adolescents' chronotype and sleep: A review of a gap in the literature

Circadian rhythms are entrained by external factors such as sunlight and social cues, but also depend on internal factors such as age. Adolescents exhibit late chronotypes, but worldwide school starts early in the morning leading to unhealthy sleep habits. Several studies reported that adolescents benefit from later school start times. However, the effect of later school start time on different outcomes varies between studies, and most previous literature only takes into consideration the social clock (i.e. local time of school starting time) but not the solar clock (e.g. the distance between school start time and sunrise). Thus, there is an important gap in the literature: when assessing the effect of a school start time on chronotype and sleep of adolescents at different locations and/or seasons, the solar clock might differ and, consistently, the obtained results. For example, the earliest school start time for adolescents has been suggested to be 08:30 hours, but this school start time might correspond to different solar times at different times of the year, longitudes and latitudes. Here, we describe the available literature comparing different school start times, considering important factors such as geographic position, nationality, and the local school start time and its distance to sunrise. Then, we described and contrasted the relative role of both social and solar clocks on the chronotype and sleep of adolescents. As a whole, we point and discuss a gap in literature, suggesting that both clocks are relevant when addressing the effect of school start time on adolescents' chronotype and sleep.

Sleep and mental health among Chinese adolescents: the chain-mediating role of physical health perception and school adjustment

OBJECTIVE

Sleep problems and their detrimental effects on adolescents' physical and mental health have received substantial attention. Prior studies have focused mainly on the direct association between sleep and mental health; however, little is known about the underlying mediating mechanism. To address this gap, the present study constructed a chain mediation model to examine the association between sleep deficiency and mental health status in adolescents, by introducing two mediating variables-physical health perception and school adjustment.

METHODS

A sample of 7530 senior high school students completed a battery of self-report questionnaires measuring their sleep duration, mental health status, physical health perception, and school adjustment. Data were collected from the Database of Youth Health at Shandong University. All the measures showed good reliability and validity in the present study. Data were analyzed using SPSS 25.0 and the SPSS PROCESS.

RESULTS

The results were as follows: (1) Sleep duration was significantly associated with physical health perception and mental health. (2) Physical health perception partially mediated the association between sleep and mental health. (3) Physical health perception and school adjustment played a chain mediating role between sleep and mental health. In conclusion, sleep not only directly associated with mental health among adolescents, but also influences mental health by the chain mediating effect of perception of physical health and school adjustment.

CONCLUSION

These findings in the present study contribute to understanding the mechanisms underlying the association between sleep and mental health and have important implications for interventions aimed at improving mental health status among adolescents in China. Our results indicated that promoting adequate sleep duration and improving sleep quality are possible key mental health promotion strategies for adolescents.

Substituting Book Reading for Screen Time Benefits Preschoolers' Sleep Health: Results from the Ulm SPATZ Health Study

Purpose

Healthy sleep is essential for the physical, cognitive, and social development of children. Several studies have reported the increase in digital media use in preschool children and its association with impaired sleep. However, there is relatively little evidence on the effects of book reading as a potentially safe alternative. The objective of this study, therefore, was to investigate whether sleep in children could benefit from book reading, and whether the negative effects of media use on sleep can be mitigated by substituting book reading for screen time.

Participants and Methods

We used longitudinal data from three consecutive waves of the SPATZ Health study, including children at the ages of 4 (n=581), 5 (n=508), and 6 (n=426) years. All data were collected by self-administered questionnaires. Parent-reported child sleep was assessed by the Children's Sleep Habits Questionnaire.

Results

Across the three waves, screen-based media use increased and was associated with lower sleep quality. In contrast, the time spent with book reading decreased; however, book reading appeared to be beneficial for children's sleep. Substitution models revealed that the theoretical substitution of an equal amount of book reading for 50% of the time spent with screen-based media benefits several domains of preschoolers' sleep health, including parasomnias, sleep anxiety, daytime sleepiness, and sleep onset delay.

Conclusion

Besides implications for population-wide and individual prevention, book reading may also be incorporated as a useful intervention to improve sleep quality in children who are already affected by sleep problems. Given that book reading is perceived as a safe alternative, the presented evidence may suffice to support recommendations in this direction.

Neurobehavioral functions during recurrent periods of sleep restriction: effects of intra-individual variability in sleep duration

STUDY OBJECTIVES

To investigate whether neurobehavioral impairments are exacerbated during successive cycles of sleep restriction and recovery in young adults, and whether a variable short sleep schedule can mitigate these impairments relative to a stable one.

METHODS

Fifty-two healthy young adults (25 males, aged: 21-28) were randomly assigned to the stable short sleep group, the variable short sleep group, or the control group in this laboratory-based study. They underwent two baseline nights of 8-hour time-in-bed (TIB), followed by two cycles of "weekday" sleep opportunity manipulation and "weekend" recovery (8-hour TIB). During each manipulation period, the stable short sleep and the control groups received 6- and 8-hour TIBs each night respectively, while the variable short sleep group received 8-hour, 4-hour, 8-hour, 4-hour, and 6-hour TIBs from the first to the fifth night. Neurobehavioral functions were assessed five times each day.

RESULTS

The stable short sleep group showed faster vigilance deterioration in the second week of sleep restriction as compared to the first. This effect was not observed in the variable short sleep group. Subjective alertness and practice-based improvement in processing speed were attenuated in both short sleep groups.

CONCLUSIONS

In young adults, more variable short sleep schedules incorporating days of prophylactic or recovery sleep might mitigate compounding vigilance deficits resulting from recurrent cycles of sleep restriction. However, processing speed and subjective sleepiness were still impaired in both short sleep schedules. Getting sufficient sleep consistently is the only way to ensure optimal neurobehavioral functioning.

CLINICAL TRIAL

Performance, Mood, and Brain and Metabolic Functions During Different Sleep Schedules (STAVAR), https://www.clinicaltrials.gov/study/NCT04731662, NCT04731662.

Construction of a model for adolescent physical and mental health promotion based on the multiple mediating effects of general self-efficacy and sleep duration

We developed a model for promoting adolescent physical and mental health (MH) to investigate the integrated pathways of physical activity (PA), MH, general self-efficacy (GSE), and sleep duration (SD) promotion among adolescents in China. The research hypotheses were tested using questionnaires, descriptive statistics, and validated factor analysis. The mean age of the respondents was 14.94 ± 1.76 years, the PA level was 2.49 [95% confidence interval (CI): 2.46-2.53], the GSE score was 2.60 (95% CI: 2.57-2.64), the SD was 436.52 min/day (95% CI: 432.89-440.15), and the total mean MH score was 1.72 (95% CI: 1.69-1.76) (model fitness index: χ2/df = 1.295, comparative fit index = 0.999, Tucker-Lewis index = 0.997, root mean square error of approximation = 0.014, standardized root mean square residual = 0.007). The SD accounted for 46.85% of the mediating effect. The adolescents exhibited moderately low PA levels, severe SD deficits, and high rates of overall MH abnormalities. Consequently, the constructed model for promoting adolescent physical health and MH was confirmed to be reliable; GSE and SD are significant factors mediating MH promotion.

Earlier Bedtime and Its Effect on Adolescent Sleep Duration

BACKGROUND AND OBJECTIVES

Sleep duration decreases by ∼10 minutes per year throughout adolescence. A circadian phase delay and changes in homeostatic sleep regulation enable adolescents to stay up later. We determine if teens are able to increase sleep duration by advancing bedtime and whether this ability changes with age.

METHODS

A younger cohort of 77 participants ranging in age from 9.9 to 16.2 years were studied annually for 3 years. An older cohort of 67 participants ranging in age from 15.0 to 20.6 years was studied only once. Annually, participants kept each of 3 different time in bed (TIB) schedules (7, 8.5, and 10 hours) for 4 consecutive nights. Participants kept their habitual weekday rise times; TIB was altered by advancing bedtimes. We report polysomnography-measured sleep durations from the fourth night of the TIB schedule.

RESULTS

Despite increases in sleep onset latency and wake after sleep onset, sleep duration increased with TIB as bedtime was advanced. Average (SE) sleep duration increased from 402.8 (1.6) minutes with 7 hours to 470.6 (2.1) minutes with 8.5 hours to 527.5 (3.0) minutes with 10 hours TIB. Sleep duration decreased with age (1.55 [0.48] minutes/year), but the TIB effect on sleep duration did not (TIB by age interaction, P = .42).

CONCLUSIONS

Adolescents can substantially increase sleep duration by advancing bedtime, and this ability does not change between ages 10 and 21 years. Additional research is needed to determine how to translate these findings from experiment-controlled sleep schedules to real-world sleep duration increases.

School-Based Sleep Education Program for Children: A Cluster Randomized Controlled Trial

Insufficient sleep contributes negatively to child developmental processes and neurocognitive abilities, which argues the need for implementing interventions to promote sleep health in children. In this study, we evaluated the effectiveness of a multimodal and multilevel school-based sleep education program in primary school children using a cluster randomized controlled design. Twelve schools were randomly assigned to either the sleep education or nonactive control groups. The sleep education group included a town hall seminar, small class teaching, leaflets, brochures, and a painting competition for children. Parents and teachers were invited to participate in a one-off sleep health workshop. Parental/caregiver-reported questionnaires were collected at baseline and 1-month follow-up. A total of 3769 children were included in the final analysis. There were no significant improvements observed in the sleep-wake patterns, daytime functioning, and insomnia symptoms between the two groups at follow-up, whereas the intervention group had significantly improved parental sleep knowledge than the controls (paternal: adjusted mean difference: 0.95 [95% confidence interval (CI): 0.18 to 1.71]; maternal: adjusted mean difference: 0.87 [95% CI: 0.17 to 1.57]). In addition, children receiving the intervention had a lower persistence rate of excessive beverage intake (adjusted odds ratio: 0.49 [95% CI: 0.33 to 0.73]), and experienced greater reductions in conduct problems (adjusted mean difference: 0.12 [95% CI: 0.01 to 0.24]) compared with the controls at 1-month of follow-up. Moreover, a marginally significant reduction for emotional problems in the intervention group was also observed (adjusted mean difference: 0.16 [95% CI: -0.00 to 0.32]). These findings demonstrated that school-based sleep education was effective in enhancing parental sleep knowledge and improving behavioral outcomes in children, but not sufficient in altering the children's sleep-wake patterns and sleep problems.

A better alignment between chronotype and school timing is associated with lower grade retention in adolescents

Schools start early in the morning all over the world, contrasting with adolescents' late chronotype. Interestingly, lower academic performance (i.e. grades or qualifications) was associated with later chronotypes. However, it is unclear whether it is a direct effect of chronotype or because students attend school too early to perform at their best. Moreover, little is known about how this affects students' academic success beyond their grades. To address this gap in knowledge, we studied how school timing and chronotype affect grade retention (i.e. repeat a year) in a unique sample of students randomly assigned to one of three different school timings (starting at 07:45, 12:40, or 17:20). Even when controlling for academic performance, we found that later chronotypes exhibit higher odds of grade retention only in the morning, but not in later school timings. Altogether, ensuring a better alignment between school timing and students' biological rhythms might enhance future opportunities of adolescents.

School Attendance, Chronotype, and Day-of-the-Week Effect in Adolescent Male Basketball Players

Adolescents' conflict between circadian rhythm and early school start time is more pronounced in evening chronotypes, who tend to reduce sleep duration during school days compensating during the free days by oversleeping (i.e., social jetlag). Cumulative weekly sleep debt may impair sport performance, which relies on physical and cognitive skills modulated by sleep. We hypothesized that chronotype predicts sport performance, and that it may interact with the day of the week. Moreover, given the role sleep plays in motor memory consolidation, we tested the hypothesis that school attendance, and the related chronic sleep deprivation, might be detrimental for participants in a training phase. Ninety-three adolescent male basketball players performed multiple free throw sessions (n = 7880) during both the school and holiday periods. Chronotype and its interaction with the day of the week significantly predicted shooting accuracy when attending school, but not on holidays. Evening types' performance gradually decreased from Monday to Friday. Participants with a more unstable performance (i.e., who did not complete the acquisition of the free throw motor scheme) worsened their accuracy when attending school. Our results suggest that the impact of chronotype and day of the week on sport performance is related to the presence of an externally imposed sleep/wake schedule and is consistent with evening types' increased likelihood of experiencing social jetlag. Possibly due to early school start time, attending school worsened the performance of participants in a training phase. Further investigations are required to assess whether reducing the mismatch between biological and social clocks might improve sport performance, along with other aspects of adolescents' life.

Secular trends of sleep-wake patterns in Hong Kong preschoolers

OBJECTIVE

To evaluate the secular trends of sleep-wake patterns of Hong Kong preschool children.

METHODS

Kindergartens from the four geographical regions of Hong Kong were randomly invited to take part in a sleep survey in 2012 and again in 2018. The parent-completed questionnaire provided information on socioeconomic status (SES), children's, and parental sleep-wake patterns. Secular trends and risk factors associated with short sleep duration in preschoolers were explored.

RESULTS

A sample of 5048 preschool children was included in the secular comparison, with 2306 and 2742 from the 2012 and 2018 surveys, respectively. A higher percentage of children in 2018 (41.1% vs 26.7%, p < 0.001) did not achieve the recommended sleep duration. During the survey years, sleep duration decreased by 13 ([95%CI: 18.5 to -8.1]) and 18 min ([95%CI: 23.6 to -12.2]) on weekdays and weekends, respectively. The overall trend of nap decrease was not significant. Sleep onset latency significantly increased on both weekdays (6 min [95%CI: 3.5 to 8.5]) and weekends (7 min [95%CI: 4.7 to 9.9]). Children's sleep duration was positively correlated with parental sleep duration with a correlation coefficient ranging from 0.16 to 0.27 (p < 0.001).

CONCLUSIONS

A significant proportion of Hong Kong preschool children did not achieve the recommended amount of sleep. A downward secular trend in sleep duration was observed during the survey period. Public health measures to improve sleep duration in preschool children should be a high priority.

Attachment to Mother and Father, Sleep, and Well-Being in Late Middle Childhood

The security of attachment has been related to several advantageous developmental outcomes, such as good sleep quality and higher well-being indicators. However, few studies concern the associations between attachment dimensions to both parents, sleep, and well-being in late middle childhood. Our study aims to expand knowledge in this area, clarifying the above-mentioned associations by considering the secure base and safe haven dimensions of attachment. We also investigate the role of sleep as a mediator of the relationship between attachment and well-being. The 258 participants (49.2% girls, mean age = 11.19, SD = 0.85) completed self-report questionnaires regarding attachment (KSS), sleep (SSR), and well-being (CHIP-CE). The results show significant associations between attachment to both parents (0.40 ** ≤ r ≤ 0.61 **) and between attachment security, sleep (-0.21 ** ≤ r ≤ -0.35 **) and child well-being (0.42 ** ≤ r ≤ 0.47 **). Besides, sleep quality partially mediated the relations between all attachment dimensions to both parents and well-being. The results are discussed in light of attachment theory, focusing on the comparison between attachment to mother and father as a valid framework to unravel differences in child well-being, with sleep as a process that can help to explain the mechanisms through which attachment security enables subjective perceptions of well-being.

Understanding the Need for Sleep to Improve Cognition

The restorative function of sleep is shaped by its duration, timing, continuity, subjective quality, and efficiency. Current sleep recommendations specify only nocturnal duration and have been largely derived from sleep self-reports that can be imprecise and miss relevant details. Sleep duration, preferred timing, and ability to withstand sleep deprivation are heritable traits whose expression may change with age and affect the optimal sleep prescription for an individual. Prevailing societal norms and circumstances related to work and relationships interact to influence sleep opportunity and quality. The value of allocating time for sleep is revealed by the impact of its restriction on behavior, functional brain imaging, sleep macrostructure, and late-life cognition. Augmentation of sleep slow oscillations and spindles have been proposed for enhancing sleep quality, but they inconsistently achieve their goal. Crafting bespoke sleep recommendations could benefit from large-scale, longitudinal collection of objective sleep data integrated with behavioral and self-reported data.

Are We Ready to Implement Circadian Hygiene Interventions and Programs?

Circadian hygiene, a concept not to be confused with the notion of public or social hygiene, should be discussed among experts and society. Light-dark cycles and other possible synchronizers of the human circadian timing system affect ways of life, including sleeping, eating, working and physical activity. Some of these behaviors have also been investigated individually as synchronizers (e.g., eating times). Therefore, the knowledge held today about circadian rhythms, and their implications for health, allows future perspectives in this field to be mapped. The present article summarizes the latest knowledge on factors influencing circadian rhythms to discuss a perspective for the future of health promotion based on circadian hygiene. However, it is important to highlight that circadian hygiene is the product of an imbrication of individual and societal involvement. First, it is important to adopt practices and devise public health policies in line with circadian hygiene. Second, individual healthy habits require internal rhythms to be examined. Last, the research agenda on circadian hygiene can be developed on a public as well as individual level, raising the question as to how much society is willing to embrace this change.

Middle school start times and young adolescent sleep, behavioral health, and academic performance outcomes: a narrative review

STUDY OBJECTIVES

This narrative review aims to synthesize peer-reviewed and gray literature research that associates middle school start times to adolescent sleep, health, and academic performance.

METHODS

A systematic search of publications in PubMed, Scopus, ERIC, APA PsycInfo, CINAHL, ProceedingsFirst, and ProQuest Dissertations and Theses from 2002-2020 was conducted. Studies with middle school students that had either an empirical evaluation of the implementation of a change in school start time or a comparison of schools with different school start times, and which also reported outcomes related to sleep and health and quantitative academic measures were included. School characteristics, student demographics, study design, start times, and outcomes were extracted from the full-text review.

RESULTS

The review identified 1,136 articles; after removing duplicates, 845 were screened. Following title and abstract review, 18 articles were eligible for full-text review. Nine studies did not meet inclusion criteria. Half of the reviewed 10 studies used cross-sectional designs, 8 evaluated sleep, 6 evaluated behavioral health, and 3 evaluated academic performance.

CONCLUSIONS

Late middle school start times can improve adolescents' sleep and reduce daytime sleepiness by increasing total sleep time and delaying waketime. The current studies provide promising evidence that late-start times can improve tardiness, executive function, negative affect and mood, grade-point average, and standardized test scores. Methodologically robust research on delayed middle school start times can inform public policy and promote change.

CITATION

Barlaan DR, Pangelinan BA, Johns A, Schweikhard A, Cromer LD. Middle school start times and young adolescent sleep, behavioral health, and academic performance outcomes: a narrative review. J Clin Sleep Med. 2022;18(11):2681-2694.

Daytime sleepiness in elementary school students: the role of sleep quality and chronotype

OBJECTIVE

To investigate the occurrence of daytime sleepiness and associated sleep factors in a sample of elementary school students who attended school in the afternoon schedule.

METHODS

Sleep data from 363 Brazilian public school students (12.78 ± 1.36 years, 206 girls) were obtained by applying questionnaires in classrooms. All subjects attended school in the afternoon schedule, with classes starting between 1:00 and 1:20 p.m. Daytime sleepiness was assessed by the pediatric daytime sleepiness scale; sleep quality, by the mini-sleep questionnaire; and sleep patterns and chronotypes, by the Munich chronotype questionnaire. Scores equal to or greater than 15 pediatric daytime sleepiness scale points were considered as excessive daytime sleepiness. The predictive power of sleep variables on daytime sleepiness was evaluated by a multiple linear regression.

RESULTS

The subjects in the sample had an average time in bed greater than nine hours both on school days and on weekends. Nevertheless, 52.1% had an average pediatric daytime sleepiness scale score equal to or greater than 15 points, indicative of excessive daytime sleepiness. As for their quality of sleep, 41.1% had a very altered sleep. We observed, by a multiple linear regression, that quality of sleep (β = 0.417), chronotype (β = 0.174), mid-sleep on school days (β = 0.138), and time in bed (β = - 0.091) were all significant in predicting daytime sleepiness.

CONCLUSION

This study showed the occurrence of excessive daytime sleepiness in non-sleep deprived students who attended school in the afternoon. The worst quality of sleep and eveningness had a greater predictive power on daytime sleepiness than time in bed. Therefore, we must consider other factors in addition to sleep duration when planning interventions for daytime sleepiness.

Chronotype at the beginning of secondary school and school timing are both associated with chronotype development during adolescence

The misalignment between late chronotypes and early school start times affect health, performance and psychological well-being of adolescents. Here we test whether, and how, the baseline chronotype (i.e. chronotype at the beginning of secondary school) and the school timing affect the magnitude and the direction of the developmental change in chronotype during adolescence. We evaluated a sample of Argentinian students (n = 259) who were randomly assigned to attend school in the morning (07:45 a.m.–12:05 p.m.), afternoon (12:40 p.m.–05:00 p.m.) or evening (05:20 p.m.–09:40 p.m.) school timings. Importantly, chronotype and sleep habits were assessed longitudinally in the same group of students along secondary school (at 13–14 y.o. and 17–18 y.o.). Our results show that: (1) although chronotypes partially align with class time, this effect is insufficient to fully account for the differences observed in sleep-related variables between school timings; (2) both school timing and baseline chronotype are independently associated with the direction and the magnitude of change in chronotype, with greater delays related to earlier baseline chronotypes and later school timings. The practical implications of these results are challenging and should be considered in the design of future educational timing policies to improve adolescents’ well-being.

Boosting Student Wellbeing Despite a Pandemic: Positive Psychology Interventions and the Impact of Sleep in the United Arab Emirates

Positive psychology interventions hold great promise as schools around the world look to increase the wellbeing of young people. To reach this aim, a program was developed to generate positive emotions, as well as improve life satisfaction, mental toughness and perceptions of school kindness in 538 expatriate students in Dubai, United Arab Emirates. Starting in September 2019, the program included a range of positive psychology interventions such as gratitude, acts of kindness and mental contrasting as examples. Life satisfaction and mental toughness at mid-year were sustained or grew by the end of the year. Positive affect, emotional wellbeing and social wellbeing increased at post-intervention 1, compared to baseline. However, this improvement reverted to baseline levels at post-intervention 2, when data were collected during the COVID-19 pandemic. Only psychological wellbeing, negative affect, perceptions of control, and school kindness were increased at post-intervention 2. During the lockdown, students moved less, but slept and scrolled more. Those who extended their sleep duration reported greater wellbeing. Boosting wellbeing through the use of positive psychology interventions works – even in a pandemic – and extended sleep duration appears to be a driving factor for this observation.

Impact of a Behavioral Sleep Intervention in Adolescents With ADHD: Feasibility, Acceptability, and Preliminary Effectiveness From a Pilot Open Trial

OBJECTIVE

An open trial tested the feasibility, acceptability, and preliminary effectiveness of a behavioral sleep intervention in adolescents with ADHD.

METHOD

Fourteen adolescents (ages 13-17 years; 50% male) with ADHD and co-occurring sleep problems received the cognitive-behavioral-based Transdiagnostic Sleep and Circadian Intervention for Youth (TranS-C). Adolescent, parent, and teacher ratings, actigraphy, and daily sleep diaries were collected at pre-intervention, post-intervention, and 3-month follow-up.

RESULTS

Adolescents experienced moderate to large improvements in sleep, mental health symptoms, and daily life executive functioning from pre-treatment to post-treatment, and improvements were generally maintained at 3 months. Pre-intervention, 71.4% of adolescents were classified as poor sleepers and this was reduced to 21.4% and 28.6% at post-treatment and follow-up, respectively.

CONCLUSION

This study provides strong preliminary evidence that TranS-C improves sleep and associated outcomes in adolescents with ADHD and co-occurring sleep problems. A randomized controlled trial is needed to rigorously test the efficacy of TranS-C in this population.

Sleep improvements on days with later school starts persist after 1 year in a flexible start system

Early school times fundamentally clash with the late sleep of teenagers. This mismatch results in chronic sleep deprivation posing acute and long-term health risks and impairing students' learning. Despite immediate short-term benefits for sleep, the long-term effects of later starts remain unresolved. In a pre-post design over 1 year, we studied a unique flexible school start system, in which 10–12th grade students chose daily between an 8:00 or 8:50AM-start. Missed study time (8:00–8:50) was compensated for during gap periods or after classes. Based on 2 waves (6–9 weeks of sleep diary each), we found that students maintained their ~ 1-h-sleep gain on later days, longitudinally (n = 28) and cross-sectionally (n = 79). This gain was independent of chronotype and frequency of later starts but attenuated for boys after 1 year. Students showed persistently better sleep quality and reduced alarm-driven waking and reported psychological benefits (n = 93) like improved motivation, concentration, and study quality on later days. Nonetheless, students chose later starts only infrequently (median 2 days/week), precluding detectable sleep extensions in the flexible system overall. Reasons for not choosing late starts were the need to make up lost study time, preference for extra study time and transport issues. Whether flexible systems constitute an appealing alternative to fixed delays given possible circadian and psychological advantages warrants further investigation.

A collaborative approach to adopting/adapting guidelines. The Australian 24-hour movement guidelines for children (5-12 years) and young people (13-17 years): An integration of physical activity, sedentary behaviour, and sleep

Abstract

Background

In 2018, the Australian Government updated the Australian Physical Activity and Sedentary Behaviour Guidelines for Children and Young People. A requirement of this update was the incorporation of a 24-hour approach to movement, recognising the importance of adequate sleep. The purpose of this paper was to describe how the updated Australian 24-Hour Movement Guidelines for Children and Young People (5 to 17 years): an integration of physical activity, sedentary behaviour and sleep were developed and the outcomes from this process.

Methods

The GRADE-ADOLOPMENT approach was used to develop the guidelines. A Leadership Group was formed, who identified existing credible guidelines. The Canadian 24-Hour Movement Guidelines for Children and Youth best met the criteria established by the Leadership Group. These guidelines were evaluated based on the evidence in the GRADE tables, summaries of findings tables and recommendations from the Canadian Guidelines. We conducted updates to each of the Canadian systematic reviews. A Guideline Development Group reviewed, separately and in combination, the evidence for each behaviour. A choice was then made to adopt or adapt the Canadian recommendations for each behaviour or create de novo recommendations. We then conducted an online survey (n=237) along with three focus groups (n=11 in total) and 13 key informant interviews. Stakeholders used these to provide feedback on the draft guidelines.

Results

Based on the evidence from the Canadian systematic reviews and the updated systematic reviews in Australia, the Guideline Development Group agreed to adopt the Canadian recommendations and, apart from some minor changes to the wording of good practice statements, maintain the wording of the guidelines, preamble, and title of the Canadian Guidelines. The Australian Guidelines provide evidence-informed recommendations for a healthy day (24-hours), integrating physical activity, sedentary behaviour (including limits to screen time), and sleep for children (5-12 years) and young people (13-17 years).

Conclusions

To our knowledge, this is only the second time the GRADE-ADOLOPMENT approach has been used to develop movement behaviour guidelines. The judgments of the Australian Guideline Development Group did not differ sufficiently to change the directions and strength of the recommendations and as such, the Canadian Guidelines were adopted with only very minor alterations. This allowed the Australian Guidelines to be developed in a shorter time frame and at a lower cost. We recommend the GRADE-ADOLOPMENT approach, especially if a credible set of guidelines that was developed using the GRADE approach is available with all supporting materials. Other countries may consider this approach when developing and/or revising national movement guidelines.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-021-01236-2.

Adolescent sleep health and school start times: Setting the research agenda for California and beyond: A research summit summary: A research summit summary

In fall 2019, California passed and signed into law SB328, the first US statewide legislation explicitly designed to protect adolescent sleep health by requiring most California public school districts to start no earlier than 8:00 AM for middle schools and 8:30 AM for high schools. Recognizing the unique opportunity presented by the bill's 3-year implementation period, a group of experts in adolescent sleep and school start times held a virtual summit on January 22-23, 2021 to (1) summarize the research on adolescent sleep and school start time change; (2) develop recommendations for relevant, refined, and innovative research areas and research questions; (3) provide input regarding research design, methodology, and implementation; and (4) offer a forum for networking, exchanging ideas, and establishing interdisciplinary research collaborations. Participants represented a multidisciplinary range of academic backgrounds including sleep and circadian biology, neuroscience, education, medicine, public health, mental health, safety, public policy, economics, implementation science, criminology, diversity studies, and science communication. This paper summarizes summit presentations regarding current knowledge on adolescent sleep health and school start times and key research recommendations from small group workshops on topics including research design and tools, methodological issues, sleep health disparities, logistical challenges in conducting school-based research, public-health impact, and novel and expanded approaches to research.

Teachers' preference for later school start times

Early morning school start times conflict with biologically determined sleep phase preference and thus contribute to common sleep deficits. This conflict is most pronounced in adolescents, and numerous studies have confirmed that later school start times are beneficial for their sleep and health. However, the conflict continues to exist beyond adolescence and, accordingly, also teachers might benefit from later school start times, but this has gained little attention so far. Importantly, teachers’ resistance to delay school start time is one of the key barriers for a successful implementation and, therefore, teachers’ school start time preferences and influencing factors are important to consider. To this end, we conducted an online survey. Teachers (n = 694, 56.1% female) from 17 high schools in Zurich, Switzerland, participated in the study. They indicated their school start time preference. In addition, four predictor blocks were assessed: sociodemographic, school‐/work‐related, and sleep characteristics, as well as teachers’ perception of students in the first morning lesson. Mixed models were applied to predict the preference. The majority (51%) endorsed later school start times (median preferred delay 25.2 min). School start time, sleep characteristics and perception of students in the first morning lesson were significant predictors for the preference. Thus, teachers with more misaligned sleep and higher awareness for students’ issues in the early morning were more likely to report a preference. This suggests psychoeducation about sleep biology throughout life span to be an effective measure to increase teachers’ support to delay school start time, especially because also they themselves are likely to benefit from later school start times.

Nonlinear relationship between sleep duration and non-suicidal self-injurious behaviour among Chinese adolescents

BACKGROUND

Previous studies have shown a positive association between sleep deprivation and non-suicidal self-injury (NSSI) among adolescents, but few studies have described the effects of oversleeping and weekend catch-up sleep on NSSI. The present study aimed to explore the nonlinear relationship between sleep duration and NSSI among Chinese adolescents.

METHODS

Data from China's National Adolescent Health Surveillance for the years 2014 to 2015 were collected from 15,713 students located across four provinces in China. A self-report questionnaire was used to assess sleep duration and 12-month NSSI. Binomial logistic regression models were used to examine the association between NSSI and sleep duration. The locally estimated scatter plot smoothing (LOESS) method was used to explore the associations of total NSSI number with sleep duration, and binomial regression analysis was used to test this relationship.

RESULTS

About 68.5% of adolescents reported sleeping less than 8 h on weeknights, while 37.8% of adolescents slept more than 10 h per night during weekends. The 12-month prevalence rate of NSSI was 29.4%. Compared to adolescents who reported weekend catch-up sleep of 0-1 h, those who slept < 0 h (adjusted odds ratio [aOR] = 1.38, 95% Confidence Interval [95% CI]: 1.16-1.64) had a higher risk of NSSI. Males who reported ≥3 h of weekend catch-up sleep had significantly increased odds of NSSI (aOR = 1.20, 95%CI: 1.01-1.42). Notably, a positive U-shaped association was observed between the sleep duration and the total NSSI number.

CONCLUSIONS

The findings reveal a nonlinear relationship between sleep duration and NSSI among Chinese adolescents. Therefore, it is necessary to be vigilant and screen for sleep duration among adolescents in NSSI treatment or prevention.

In-person vs home schooling during the COVID-19 pandemic: Differences in sleep, circadian timing, and mood in early adolescence

During the COVID-19 pandemic, schools around the world rapidly transitioned from in-person to remote learning, providing an opportunity to examine the impact of in-person vs remote learning on sleep, circadian timing, and mood. We assessed sleep-wake timing using wrist actigraphy and sleep diaries over 1-2 weeks during in-person learning (n = 28) and remote learning (n = 58, where n = 27 were repeat assessments) in adolescents (age M ± SD = 12.79 ± 0.42 years). Circadian timing was measured under a single condition in each individual using salivary melatonin (Dim Light Melatonin Onset; DLMO). Online surveys assessed mood (PROMIS Pediatric Anxiety and Depressive Symptoms) and sleepiness (Epworth Sleepiness Scale - Child and Adolescent) in each condition. During remote (vs in-person) learning: (i) on school days, students went to sleep 26 minutes later and woke 49 minutes later, resulting in 22 minutes longer sleep duration (all P < .0001); (ii) DLMO time did not differ significantly between conditions, although participants woke at a later circadian phase (43 minutes, P = .03) during remote learning; and (iii) participants reported significantly lower sleepiness (P = .048) and lower anxiety symptoms (P = .006). Depressive symptoms did not differ between conditions. Changes in mood symptoms were not mediated by sleep. Although remote learning continued to have fixed school start times, removing morning commutes likely enabled adolescents to sleep longer, wake later, and to wake at a later circadian phase. These results indicate that remote learning, or later school start times, may extend sleep and improve some subjective symptoms in adolescents.

Parental perception and guideline awareness of children's lifestyle behaviours at ages 5 to 14 in Singapore

INTRODUCTION

There are limited data on the descriptive lifestyle behaviour of school-age children in Singapore.

METHODS

A total of 100 parents of children ages 5 to 14 participated in a parents' proxy-reported survey. Frequency of moderate physical activity (PA) and vigorous PA was assessed, while t-tests or chi-square test was used to examine differences between weekdays and weekends for sleep, screen viewing time (SVT) and sedentary behaviour (SB).

RESULTS

Of the 100 children (68% of Chinese ethnicity, 59% boys, mean age 9.1±2.9 years), 31% were overweight or obese, with body mass index z-score of >1. For moderate and vigorous PA participation in a typical week, 32.0% and 43.0%, respectively, did not participate, while median (interquartile range) days of participation were 3 (2-3) days/week and 2 (1-3) days/week for a duration of 60 (interquartile range 30-120) minutes/session. When comparing weekends with weekdays, the means (standard deviation) of both SVT and sleep duration were higher on weekends (SVT: 4.1 [2.9] versus 3.3 [3.1] hours/day, P=0.07; sleep: 8.8 [1.5] vs 8.3 [1.3] hours/day, P=0.02), while there were no significant differences for SB. A higher proportion of children had SB of ≥10 hours/day and slept <8 hours/day on weekdays compared with on weekends (SB: 23.5% vs 20.6%, P>0.05; sleep:18.8% vs 2.1%, P<0.05), while the proportion exceeding SVT of 2 hours/day were higher on weekends than on weekdays (63.8% vs 45.4%, P=0.03). Overall, there was higher parental awareness of sleep guidelines (80.0%), but lower awareness of PA (51.0%) and SVT (59.0%) guidelines.

CONCLUSION

Lifestyle behaviours were suboptimal in Singapore children compared with existing overseas guidelines, indicating a need for an integrated guideline with greater dissemination.

Human circadian variations

Circadian rhythms, present in most phyla across life, are biological oscillations occurring on a daily cycle. Since the discovery of their molecular foundations in model organisms, many inputs that modify this tightly controlled system in humans have been identified. Polygenic variations and environmental factors influence each person's circadian rhythm, contributing to the trait known as chronotype, which manifests as the degree of morning or evening preference in an individual. Despite normal variation in chronotype, much of society operates on a "one size fits all" schedule that can be difficult to adjust to, especially for certain individuals whose endogenous circadian phase is extremely advanced or delayed. This is a public health concern, as phase misalignment in humans is associated with a number of adverse health outcomes. Additionally, modern technology (such as electric lights and computer, tablet, and phone screens that emit blue light) and lifestyles (such as shift or irregular work schedules) are disrupting circadian consistency in an increasing number of people. Though medical and lifestyle interventions can alleviate some of these issues, growing research on endogenous circadian variability and sensitivity suggests that broader social changes may be necessary to minimize the impact of circadian misalignment on health.

Changes in health promoting behavior during COVID-19 physical distancing: Utilizing wearable technology to examine trends in sleep, activity, and cardiovascular indicators of health

The COVID-19 pandemic incited unprecedented restrictions on the behavior of society. The aims of this study were to quantify changes to sleep/wake behavior and exercise behavior, as well as changes in physiological markers of health during COVID-19 physical distancing. A retrospective analysis of 5,436 US-based subscribers to the WHOOP platform (mean age = 40.25 ± 11.33; 1,536 females, 3,900 males) was conducted covering the period from January 1st, 2020 through May 15th, 2020. This time period was separated into a 68-day baseline period and a 67-day physical distancing period. To provide context and allow for potential confounders (e.g., change of season), data were also extracted from the corresponding time periods in 2019. As compared to baseline, during physical distancing, all subjects fell asleep earlier (-0.15 hours), woke up later (0.29 hours), obtained more sleep (+0.21 hours) and reduced social jet lag (-0.13 hours). Contrasting sleep behavior was seen in 2019, with subjects falling asleep and waking up at a similar time (-0.01 hours; -0.03 hours), obtaining less sleep (-0.14 hours) and maintaining social jet lag (+0.06 hours) in corresponding periods. Individuals exercised more intensely during physical distancing by increasing the time spent in high heart rate zones. In 2020, resting heart rate decreased (-0.90 beats per minute) and heart rate variability increased (+0.98 milliseconds) during physical distancing when compared to baseline. However, similar changes were seen in 2019 for RHR (-0.51 beats per minute) and HRV (+2.97 milliseconds), suggesting the variation may not be related to the introduction of physical distancing mandates. The findings suggest that individuals improved health related behavior (i.e., increased exercise intensity and longer sleep duration) during physical distancing restrictions. While positive changes were seen to cardiovascular indicators of health, it is unclear whether these changes were a direct consequence of behavior change.

COVID-19 pandemic impact on sleep habits, chronotype, and health-related quality of life among high school students: a longitudinal study

STUDY OBJECTIVES

The COVID-19 pandemic has challenged the population of affected areas in multiple dimensions. Adolescents have been especially affected with school closure and home confinement. The impact of the pandemic on sleep habits and quality of sleep and quality of life among adolescents has not been adequately characterized. We hypothesized that the COVID-19 pandemic has induced an evening shift of the daily rhythm among adolescents and adversely affected sleep quality and quality of life of high school students.

METHODS

Students were questioned about their usual bed and wake-up times and answered the Pittsburgh Sleep Quality Index Questionnaire, the Epworth Sleepiness Scale, the Horne-Osteberg Morningness-Eveningness Questionnaire, and the World Health Organization Quality of Life Questionnaire-abbreviated version before and during the pandemic.

RESULTS

Ninety-four students (64% females, aged 15 ± 1 years) participated in both phases of the study. Students delayed bed and wake-up times by 1.5 (0.5-2.0) and 2.0 (1.5-2.5) hours, respectively. Chronotype (per the Morningness-Eveningness Questionnaire) shifted toward eveningness during the pandemic. Sleep duration increased and quality of sleep (per the Pittsburgh Sleep Quality Index) improved only among those students with shorter sleep duration before the pandemic. During the pandemic, the physical and psychological domains of the World Health Organization Quality of Life Questionnaire worsened but the environmental domain improved as compared with the study before the pandemic.

CONCLUSIONS

High school students have delayed bed and wake-up times and shifted chronotype toward eveningness during the COVID-19 pandemic. The worsening of the physical and psychological World Health Organization Quality of Life Questionnaire domains and improvement in the environmental domain highlight the conflicting experiences that high school students are facing during the COVID-19 pandemic.

Changing school start times: impact on sleep in primary and secondary school students

STUDY OBJECTIVES

To examine the impact of changing school start times on sleep for primary (elementary school: ES) and secondary (middle and high school: MS/HS) students.

METHODS

Students (grades 3-12) and parents (grades K-12) were surveyed annually, before and for 2 years after school start time changes (ES: 60 min earlier, MS: 40-60 min later; HS: 70 min later). Student sleep and daytime sleepiness were measured with school-administered student surveys and parent-proxy online surveys.

RESULTS

Approximately 28,000 students annually completed surveys (~55% White, ~21% free/reduced lunch [FRL]). One-year post-change, weekday bedtimes and wake times were slightly earlier for ES students, with an 11-min decrease in sleep duration. MS and HS students reported slightly later weekday bedtimes, significantly later wake times, and significantly longer sleep duration (MS: 29 min; HS: 45 min). The percent of ES students reporting sufficient sleep duration, poor sleep quality, or daytime sleepiness did not change, but the percent of MS and HS students reporting sufficient sleep duration significantly increased and clinically significant daytime sleepiness decreased. All results were maintained at the 2-year follow-up. Benefits of later start times were similar across racial and free/reduced lunch groups.

CONCLUSIONS

This is the first large scale, longitudinal, and representative study to concurrently examine the impact of changing school start times across students in primary/secondary school. Findings suggest a minimal impact of earlier start times on ES students' sleep or daytime sleepiness, while further supporting the significant benefits of delaying MS and HS start times on student sleep and daytime sleepiness.

Sleep, Anxiety, and Academic Performance: A Study of Adolescents From Public High Schools in China

Purpose: Sleep is essential for optimal learning across the developmental pathways. This study aimed to (1) explore whether school start and end times and screen time influenced sleep disturbances in adolescents during the lockdown in China and (2) investigate if sleep disturbances at night and sleep-related impairment (daytime fatigue) influenced adolescents' academic performance and anxiety levels. Methods: Ninety-nine adolescents aged 15-17 years old were recruited from two public schools in Baishan City Jilin Province, China. An online questionnaire was distributed including questions on adolescents' demographics, screen time habits, academic performance, anxiety level, sleep disturbances, and sleep-related impairment. Results: Adolescents who started school earlier and ended school later had a greater severity of sleep disturbances and sleep-related impairment compared with students who started school later and finished earlier. Adolescents who engaged in screen time at bedtime were more likely to have a greater severity of sleep-related impairment than students who reported no screen time use at bedtime. Adolescents who had a greater severity of sleep disturbances had higher anxiety and higher academic achievements than adolescents with less sleep disturbances. Finally, 79.7% of adolescents reported their total sleep duration as <8 h. Conclusions: Adolescents are experiencing sleep disturbances to manage academic demands during COVID-19, which in turn is having a wider impact on their mental health. Many schools internationally have continued to provide online education to students, longitudinal studies on how COVID-19 has influenced adolescents sleep and mental health would be beneficial in understanding the impact of the pandemic.

Memory performance following napping in habitual and non-habitual nappers

Study Objectives

Afternoon naps benefit memory but this may depend on whether one is a habitual napper (HN; ≥1 nap/week) or non-habitual napper (NN). Here, we investigated whether a nap would benefit HN and NN differently, as well as whether HN would be more adversely affected by nap restriction compared to NN.

Methods

Forty-six participants in the nap condition (HN-nap: n = 25, NN-nap: n = 21) took a 90-min nap (14:00–15:30 pm) on experimental days while 46 participants in the Wake condition (HN-wake: n = 24, NN-wake: n = 22) remained awake in the afternoon. Memory tasks were administered after the nap to assess short-term topographical memory and long-term memory in the form of picture encoding and factual knowledge learning respectively.

Results

An afternoon nap boosted picture encoding and factual knowledge learning irrespective of whether one habitually napped (main effects of condition (nap/wake): ps < 0.037). However, we found a significant interaction for the hippocampal-dependent topographical memory task (p = 0.039) wherein a nap, relative to wake, benefitted habitual nappers (HN-nap vs HN-wake: p = 0.003) compared to non-habitual nappers (NN-nap vs. NN-wake: p = 0.918). Notably for this task, habitual nappers’ performance significantly declined if they were not allowed to nap (HN-wake vs NN-wake: p = 0.037).

Conclusions

Contrary to concerns that napping may be disadvantageous for non-habitual nappers, we found that an afternoon nap was beneficial for long-term memory tasks even if one did not habitually nap. Naps were especially beneficial for habitual nappers performing a short-term topographical memory task, as it restored the decline that would otherwise have been incurred without a nap.

Clinical Trial Information

NCT04044885.

Lecture start time and sleep characteristics: Analysis of daily diaries of undergraduate students from the LoST-Sleep project

OBJECTIVES

Emerging evidence shows that later high school start times are associated with increased sleep duration; however, little is known if this extends to the university setting. This study investigated associations of first lecture start times with sleep characteristics among university students.

DESIGN

Daily diaries.

SETTING

Lincoln, UK.

PARTICIPANTS

One hundred and fifty-five undergraduate students completed 7-night sleep diaries MEASUREMENTS: Of the plausible lecture-day diaries (Monday-to-Friday, expected N = 755 days), 567 days were lecture days (M = 3.8 lecture-days per student, SD = 1.1). The Consensus Sleep Diary was used to collect sleep characteristics. Two-level multilevel mixed effect generalized linear models were employed in the analyses.

RESULTS

Seventy-five percent of first lectures occurred before noon. Students reported short sleep (M = 7.0 hours, SD = 1.9) and fewer reported highest levels of sleep quality (42.8%) and restfulness (24.8%) when first lectures started at 09:00 or 09:30 compared to 10:00 or later. Every hour delay of first lecture start time was associated with 15.1 (95% confidence interval [CI]: 9.5; 20.7) minutes increase in sleep duration and higher odds of reporting the highest levels of sleep quality and restfulness. Focusing on attended lectures starting before noon, hourly delay of first lecture start time was associated with 37.4 (95% CI: 22.0; 52.8) minutes increased sleep duration. Bedtime, sleep time, and sleep onset latency were not significantly associated with first lecture start times.

CONCLUSION

This study found that undergraduate students had longer sleep and healthier sleep quality when university first lectures started later. The earliest lecture start time that afforded sufficient sleep duration for students was 10:00.

Circadian rhythm abnormalities during the COVID-19 outbreak related to mental health in China: a nationwide university-based survey

OBJECTIVE/BACKGROUND

School closure and home quarantine has been implemented worldwide during the coronavirus disease 2019 (COVID-19) outbreak. The study aims to assess the associations of circadian rhythm abnormalities (CRA) during the COVID-19 outbreak with mental health in Chinese undergraduates.

METHODS

A nationwide cross-sectional university-based survey was conducted from 4th February to 12th, 2020. Based on different geographical locations and purposive sampling approach, 19 universities from 16 provinces or municipalities in the mainland of China were selected. A total of 14,789 participants were recruited by using multistage stratified random sampling. The data of CRA were collected by self-reported questionnaires consist of four items involved rest-activity cycle, diet rhythm, wake up rhythm and sleep rhythm. The Patient Health Questionnaire and the Generalized Anxiety Disorder were applied to evaluate the symptoms of depression and anxiety. Chi-square test and ordinal logistic regression models were used to describe the distributions and associations of CRA and mental health.

RESULTS

A total of 11,787 students [female: 6731(57.1%)] aged 15-26 years old (M = 20.45, SD = 1.76) were analyzed (response rate: 79.7%). The results showed the percentage of CRA were 17.5-28.7%. The prevalence of depression and anxiety were significantly higher in students with single CRA. Students who reported the coexistence of four CRA were more likely to be with the symptoms of depression (OR: 4.43, 95% CI: 3.91-5.03) and anxiety (OR: 3.11, 95% CI: 2.70-3.60). Dose-response relationships were found between multiple CRA and mental problems.

CONCLUSION

Circadian rhythm abnormalities are positively associated with mental health among university studies. Mental health care is needed for college students during the COVID-19 epidemic period.

Chronobiology and the case for sleep health interventions in the community

Our sleep-wake cycle is determined by the interaction between our homeostatic sleep drive and circadian rhythm. Each of us has a personalised biological rhythm or chronotype that determines the optimal time to fall asleep and wake up. Chronic sleep deprivation has been linked to the development of several physical and mental health disorders, as well as accidents and occupational errors. Around the world, growing recognition of the importance of sleep has led to the adoption of practices that promote sleep health. Given that Singaporeans were consistently found to be one of the most sleep-deprived populations in the world, we believe that there is an urgent need to pursue the introduction of community-based sleep health interventions here. This includes sleep education and promotion of sleep hygiene, adopting practices to reduce social jetlag and improve sleep health, and enhancing screening and treatment of sleep disorders.

Sleep habits and circadian preferences in school-aged children attending a Mexican double-shift school system

OBJECTIVE

To determine the differences between sleep habits and circadian preference in school-aged children attending a Mexican double-shift school system.

METHODS

This cross-sectional study consisted of 400 elementary public-school children (mean age = 10.77, SD = 0.70 y, from fourth, fifth and sixth grades) in Reynosa, Tamaulipas, in northeastern Mexico. Attending a double-shift school system: 200 from the morning shift and 200 in the afternoon shift. Specific questions regarding sleep habits were collected and for circadian preference, the Morningness-Eveningness Scale for Children (MESC) was used.

RESULTS

Multivariate analysis reported no sex differences. Children attending at the morning shift during weekdays rose earlier, reported shorter time in bed and earlier midpoint of sleep than those in the afternoon shift. On weekends, morning shift children went to bed later than afternoon shift. Morning shift reported greater social jetlag, shorter average sleep length and more sleep deficit than afternoon shift. During weekdays and weekends evening type children went to bed later, rose later and reported later midpoint of sleep. Also, evening type reported more social jetlag than morning types.

CONCLUSION

This study suggests that early school start times can have a detrimental effect on Mexican children. Moreover, the morning shift children may be at more risk of poor health due to the higher social jetlag, as well as a higher tendency to be sleep deprived. On the other hand, the afternoon shift represents an important social environment that allows children to follow their natural physiological needs and a more optimal sleep health.

Update on school-based sleep education programs: how far have we come and what has Australia contributed to the field?

OBJECTIVE

School-based sleep education programs help to promote sleep health information to many children and adolescents. The aim of this systematic review was to identify and describe school-based sleep education programs, to update previous reviews and identify recent advances and improvements in this field worldwide.

METHODS

Four electronic databases were searched. Eligibility criteria included children aged 5-18 years, sleep education intervention conducted in a school setting, and at least one pre-post-measure of a sleep variable.

RESULTS

A total of 32 articles met eligibility criteria with Australian sleep researchers constituting ∼ one quarter of these studies. Studies dated from 2007 to 2020 with sample sizes ranging from 9 to 3713 students. The majority of participants were high school students and predominantly female. Education programs generally took 4-6 weeks and content was consistent across studies. Overall, exposure to sleep education increased sleep knowledge, however changes in sleep behaviour variables and secondary outcome variables (eg, mental health; cognitive function; sleep hygiene practices) presented varied results. Studies conducted since 2015 were more likely to be randomised controlled trials and to include more interactive, online designs utilising innovative content such as mindfulness.

CONCLUSIONS

An exponential growth in school sleep education programs was identified since 2016. Future studies should consider utilising objective sleep measures, longer-term follow-ups, innovative delivery methods, and stronger attempts at implementing a knowledge-to-action approach for more sustainable programs.

School closure during the coronavirus disease 2019 (COVID-19) pandemic - Impact on children's sleep

OBJECTIVE

To evaluate the sleep habits of school-going children before and during school closure in the national lockdown period (called 'Circuit Breaker' or CB in Singapore) due to the COVID-19 pandemic.

METHODS

Cross-sectional, anonymous, online, population-based survey questionnaire was administered to parents aged 21 years and above with children aged between 3 and 16 years attending pre-school, primary or secondary school (equivalent to kindergarten, middle and-high school) and residing in Singapore. Sleep duration in relation to various daily activities including academic activities, physical exercise, and screen time was evaluated pre-CB and during CB.

RESULTS

Data from 593 participants were analyzed. Pre-CB, the overall mean (SD) sleep duration of the study population was 9.01 (1.18) hours on weekdays and 9.99 (0.94) hours on weekends. During CB, mean (SD) sleep duration overall was 9.63 (1.18) hours. Although children generally went to bed later (mean 0.65 h later), they woke up even later during CB (mean 1.27 h later), resulting in longer sleep duration (mean increase of 0.35 h). This was most evident in secondary school children (mean increase of 0.70 h). Children attending private schools (which had later start times) had increased sleep duration (mean 10.01 (SD 0.89) hours pre-CB and 10.05 (SD 0.93) hours during CB) compared to public schools (mean 9.05 (SD 0.91) pre-CB and 9.49 (SD 1.22) hours during CB).

CONCLUSIONS

School closure from the COVID-19 pandemic resulted in longer sleep duration in school-going children. Early school/academic activity start times had a significant impact on limiting children's sleep duration.

Perceived Barriers and Facilitating Factors in Implementing Delayed School Start Times to Improve Adolescent Sleep Patterns

BACKGROUND

Most adolescents in the United States do not obtain sufficient sleep. Early school start times play a significant role in adolescent sleep deprivation. Most primary and secondary schools begin classes earlier than the 8:30 am. Perceived barriers to implementing a delayed school start time have been suggested in the literature but have not been quantified. This study explored perceived barriers and facilitating factors for implementing delayed high-school start times.

METHODS

A cross-sectional study. School administrators who had delayed their school start times were invited to complete an online questionnaire ranking the perceived barriers and facilitating factors for implementing the delayed start times.

RESULTS

Most commonly cited perceived barriers were lack of a tiered bus system, school athletes missing more afternoon classes, and less time after school for athletics. Most commonly cited facilitating factors were school-administrator involvement in the decision-making process and sleep education for family members and school administrators.

CONCLUSIONS

Participants found that providing sleep education to fellow administrators, teachers, school staff members, families, and students and including them in the decision-making process positively facilitated the implementation of delayed school start times. Perceived barriers to implementation may be overcome with support from stakeholders and planning committees.

The Relationship between Sleep, Obesity, and Metabolic Health in Adolescents - a Review

In this literature review, we discuss the importance of adequate sleep and the various effects of suboptimal sleep on weight maintenance and metabolic health specifically for adolescents. Two major contributors to adolescents experiencing decreased sleep duration and quality, and thus increasing the risk for developing metabolic syndrome in adolescence as well as later in adulthood, are increased electronic screen time particularly at night and early school start times. The less time adolescents spend sleeping, the less quality sleep they obtain, and the greater the disruption of endocrine hormone function. As another consequence, adolescents are more prone to making poor food choices, from choosing relatively nutrient-poor foods to consuming excess calories without necessarily increasing their energy expenditure. These choices put adolescents at greater risk for becoming obese throughout their lifespan.

Are one-year changes in adherence to the 24-hour movement guidelines associated with flourishing among Canadian youth?

Movement behaviours (e.g., physical inactivity, short sleep duration, high screen time) are associated with mental illness but less is known about the relationship between health behaviours and positive mental health constructs such as flourishing. This study examines if changes in adherence to the Canadian 24-Hour Movement Behaviour Guidelines for Children and Youth (moderate-to-vigorous physical activity (MVPA), total screen time (ST), sleep) are associated with changes in youth flourishing over one year. Students (N = 2292) were recruited from 12 secondary schools in Canada participating in the COMPASS study. Conditional change models were used to analyze two waves of longitudinal questionnaire data from 2016-17 to 2017-18. One-year change in adherence to the MVPA, ST, and sleep duration guidelines were modeled as predictors of flourishing adjusting for covariates. Models were stratified by sex. For males only, meeting MVPA guidelines both years was associated with higher flourishing compared to males not meeting guidelines (Est:0.87, SE:0.36, p = .01). Reducing ST was associated with higher flourishing for males only relative to other males who continued to exceed the ST guidelines (Est:2.23, SE:1.04, p < .03). Longer sleep duration had the most consistent association with greater flourishing among females (Est:1.02, SE:0.3, p < .001) and males (Est:0.93, SE:0.34, p < .006), highlighting sleep as a public health priority in the context of 24-hour movement behaviours. These findings contribute to increasing calls for research examining positive mental health constructs independent of mental illness.

A comparison of sleep, depressive symptoms, and parental perceptions between U.S. and Taiwan adolescents with self-reported sleep problems

Study Objectives

Inadequate sleep is pervasive among teens worldwide, resulting in daytime sleepiness and, in some cases, depressive symptoms. In addition to their own behavioral choices, parent perceptions may also play a role in adolescent sleep. This study conducted a preliminary evaluation of the antecedents and consequences of sleep factors among adolescents in the United States and Taiwan.

Methods

Participants were adolescents with self-reported sleep concerns from academically similar schools in Taiwan (n = 548) and northern California, United States (n = 128). Questionnaires on sleep and mood were administered to both the teens and parents.

Results

While Taiwanese students’ self-reported sleep behavior was generally better than U.S. students (p < .01), Taiwanese students had higher overall self-reported sleepiness (p < .01). Furthermore, Taiwanese parents reported teen sleep durations of 6.53 ± .827 hours per night during the week (with 45% perceiving this as sufficient), while U.S. parents reported teen sleep durations of 7.22 ± .930 hours (with 27% perceiving this as sufficient). Adolescents in both cohorts had high levels of symptoms consistent with depression (Taiwan: 70%, United States: 62%), which was associated with shorter sleep times for both cohorts and evening chronotype in the Taiwanese, but not U.S., adolescents.

Conclusions

Some differences exist between Taiwanese and U.S. adolescents, with generally better sleep and less sleepiness reported among students in the United States, and Taiwanese students’ sleep influenced more strongly by chronotype. Furthermore, Taiwanese parents reported less concern about their child’s insufficient sleep, despite the fact that inadequate sleep is strongly associated with depressive symptoms for both cohorts.

Coupled network of the circadian clocks: a driving force of rhythmic physiology

The circadian system is composed of coupled endogenous oscillators that allow living beings, including humans, to anticipate and adapt to daily changes in their environment. In mammals, circadian clocks form a hierarchically organized network with a 'master clock' located in the suprachiasmatic nucleus of the hypothalamus, which ensures entrainment of subsidiary oscillators to environmental cycles. Robust rhythmicity of body clocks is indispensable for temporally coordinating organ functions, and the disruption or misalignment of circadian rhythms caused for instance by modern lifestyle is strongly associated with various widespread diseases. This review aims to provide a comprehensive overview of our current knowledge about the molecular architecture and system-level organization of mammalian circadian oscillators. Furthermore, we discuss the regulatory roles of peripheral clocks for cell and organ physiology and their implication in the temporal coordination of metabolism in human health and disease. Finally, we summarize methods for assessing circadian rhythmicity in humans.

Reducing the use of screen electronic devices in the evening is associated with improved sleep and daytime vigilance in adolescents

The use of screen electronic devices in the evening negatively affects sleep. Yet, sleep is known to be essential for brain maturation and a key factor for good academic performance, and thus is particularly critical during childhood and adolescence. Although previous studies reported associations between screen time and sleep impairment, their causal relationship in adolescents remains unclear. Using actigraphy and daily questionnaires in a large sample of students (12 to 19 years old), we assessed screen time in the evening and sleep habits over 1 month. This included a 2 week baseline phase, followed by a 40 min sleep education workshop and a 2 week interventional phase, in which participants were asked to stop using screen devices after 9 pm during school nights. During the interventional phase, we found that the reduction of screen time after 9 pm correlated with earlier sleep onset time and increased total sleep duration. The latter led to improved daytime vigilance. These findings provide evidence that restricting screen use in the evening represents a valid and promising approach for improving sleep duration in adolescents, with potential implications for daytime functioning and health.

Associations of time spent on homework or studying with nocturnal sleep behavior and depression symptoms in adolescents from Singapore

OBJECTIVE

To investigate associations of adolescents' time spent on homework/studying with nocturnal time for sleep and depression symptoms, in a competitive academic environment.

DESIGN

Cross-sectional, anonymous survey of sleep habits, school life, and health-related measures.

SETTING

Eight schools in Singapore.

PARTICIPANTS

Total 1225 adolescents aged 13-19 years.

MEASUREMENTS

Self-reported sleep behavior and time use data were collected separately for school days and weekends. Multiple regression models were used to test covariation of time spent on homework/studying with other activities, and associations of homework/studying duration with depression symptoms.

RESULTS

Time in bed for sleep and media use were inversely related with homework/studying duration on both school days and weekends, adjusting for time spent on other activities and demographic variables. Face-to-face family time and hanging out with friends were also reciprocally related with homework/studying duration on weekends. Depression scores were higher in adolescents who spent long hours on homework/studying. On school days, this was mediated by reduced time in bed for sleep. On weekends, homework/studying duration associated with depression symptoms, adjusting for time in bed and other covariates. Adolescents who spent ≥5 hours on homework/studying per day on weekends had greater symptoms of anhedonia and anxiety.

CONCLUSIONS

In a competitive academic setting, adolescents who spent more time on homework/studying spent less time on sleep, media use, and social activities. Independent of effects on sleep, long hours on homework/studying on weekends may be a risk factor for depression. Reducing adolescents' workload outside of class may benefit their sleep, schoolwork-life balance, and mental well-being.

Afternoon School Start Times Are Associated with a Lack of Both Social Jetlag and Sleep Deprivation in Adolescents

The delayed circadian timing of adolescents creates a conflict with early school start times (SSTs). We used wrist actimetry to compare sleep parameters and routine nighttime activities in middle school students attending either a morning (0700 to 1200 h) or an afternoon (1230 to 1730 h) school shift. On school days, students from both shifts (n = 21 for morning shift, n = 20 for afternoon shift, ages 12-14 years) had a similar sleep onset, but morning-shift students had an earlier sleep offset and a 1 h 45 min shorter sleep duration than their afternoon peers, who slept the recommended 8 to 10 h of daily sleep. Only morning-shift students had afternoon naps, but this afternoon sleep was not sufficient to overcome sleep deprivation. On weekends, sleep onsets and offsets did not differ between shifts. Because only morning-shift students woke up later and slept longer (2 h 3 min) on weekends, they were also the only ones who experienced social jetlag. Daily surveys on their nighttime (from 1800 to 0600 h) activities indicated there was no difference between shifts in the time spent on leisure or using electronic media during school days, but students from both shifts spent more time in these activities during the weekend. Our study confirms that early SST in adolescents is associated with sleep deprivation and suggests that schedules that start much later than typically considered may be needed to eliminate sleep deprivation in adolescents.

Later School Start Time: The Impact of Sleep on Academic Performance and Health in the Adolescent Population

The crucial role of sleep in physical and mental health is well known, especially during the developmental period. In recent years, there has been a growing interest in examining the relationship between sleep patterns and school performance in adolescents. At this stage of life, several environmental and biological factors may affect both circadian and homeostatic regulation of sleep. A large part of this population does not experience adequate sleep, leading to chronic sleep restriction and/or disrupted sleep–wake cycles. Studies investigating the effects of different sleep–wake schedules on academic achievement showed that impaired sleep quality and quantity are associated with decreased learning ability and compromised daytime functioning. This review focuses on the most recent studies that evaluated the effects of modified school start time on sleep patterns and related outcomes. Moreover, based on the available empirical evidence, we intend to propose a direction for future studies targeted to implement prevention or treatment programs by modifying sleep timing.