Changes in sleep and activity from age 15 to 17 in students with traditional and college-style school schedules

A Mixed-Methods, Multimedia Pilot Study to Investigate Sleep Irregularity Determinants Among Undergraduate Students

PURPOSE

To pilot a novel approach investigating the interplay of social and institutional determinants influencing university undergraduate student sleep patterns.

DESIGN

A two-part, three-phase mixed-methods approach.

SETTING

A mid-size US university conducted in spring and fall 2020.

PARTICIPANTS

191 undergraduate students (69 first-years, 43 second-years, 48 third-years, 31 fourth-years).

METHOD

For Part A, participants texted their activities and emotions in real time, producing a data-rich, weeklong diary of comprehensive activity logs, emoticons, multimedia submissions, and juxtapositions of ideal vs real schedules. Semi-structured contextual interviews were also conducted. For Part B, a one-time survey examined Part A insights across all class years. These diverse datasets were triangulated using thematic, comparative, and content analyses through MAXQDA software and visual mapping methods.

RESULTS

Three preliminary themes were identified as encouraging an irregular sleep schedule: a prevailing academic ethos emphasizing busyness, time management challenges, and the rhythm of institutional schedules and deadlines. An overarching theme suggests that perceptions of peer sleep habits and academic prioritization above all else could be influential across factors.

CONCLUSION

This pilot study indicates that sleep regularity among undergraduates is potentially shaped by individual choices combined with broader institutional paradigms. While it is limited by its exploratory nature, timing, and small sample size, the results highlight the promise of this methodology for more extensive studies and suggest that future interventions should emphasize systemic changes that prioritize sleep.

Longitudinal development and tracking of cardiorespiratory fitness from childhood to adolescence

BACKGROUND

Cardiorespiratory fitness (CRF) is an important indicator of health in childhood and adolescence but longitudinal studies on the development and tracking of CRF from childhood to adolescence are scarce.

OBJECTIVES

The objectives of this study were (1) to assess longitudinal development and track CRF over 10 years from childhood to adolescence, and (2) to examine potential sex differences in the development and tracking of CRF during this period.

METHODS

Participants were Icelandic children born in 1999, measured at the age of 7 (n = 190, 106 girls), 9 (n = 163, 95 girls), 15 (n = 239, 134 girls), and 17 (n = 202, 119 girls). CRF was assessed with a maximal cycle ergometer test and expressed as maximal power output (Max W) and maximal power output relative to lean mass (W/kgLM). Multilevel regression models were used to study the longitudinal development of CRF, and tracking was assessed with Spearman's rank correlation, logistic regression, and the percentage of participants remaining in low, moderate, or high CRF categories between measurements.

RESULTS

Max W and W/kgLM increased for both boys and girls up to age 15. Max W plateaued for both boys and girls while W/kgLM plateaued for girls but declined for boys from age 15 to 17. Boys had higher Max W than girls from age 15 and higher W/kgLM from age 9. CRF tracked at low to moderate levels from childhood to adolescence and at high levels in adolescence, with higher values observed for boys than girls.

CONCLUSIONS

Age 15 was a critical time point in the development of CRF, with values starting to plateau for girls and decline for boys. The results support early intervention for improved CRF in later years, with interventions targeting all children, regardless of their CRF level.

The Longitudinal Interplay between Sleep, Anthropometric Indices, Eating Behaviors, and Nutritional Aspects: A Systematic Review and Meta-Analysis

Sleep is fundamental for adolescents' healthy development but undergoes dramatic changes in quantity and quality due to the conflict between biological and social rhythms. Insufficient sleep has been associated with worse physical health status and irregular eating behaviors in adolescents. This review aims to systematically synthesize the longitudinal associations between adolescents' sleep dimensions (i.e., duration, timing, quality, and insomnia symptoms) and physical health indicators (i.e., anthropometric indices, fat percentage, and risk of obesity), eating behaviors, and nutritional aspects (i.e., type of diet related to the intake of specific foods and nutrients, amount and timing of food consumption, energy expenditure). A total of 28 longitudinal studies were included. The meta-analytic results showed that longer sleep duration, better sleep quality, and lower insomnia symptoms were associated with lower BMI and fat percentage and that shorter sleep duration (<7 h) and lower sleep quality were associated with a higher risk of obesity. Conversely, anthropometric indices were not related to sleep over time. Limited literature examined the bidirectional association between adolescents' sleep and their eating behaviors and nutritional aspects. Such knowledge sheds new light on the role of sleep for adolescents' health, highlighting the need to examine further the interplay between these variables.

Sleep Well, Study Well: A Systematic Review of Longitudinal Studies on the Interplay between Sleep and School Experience in Adolescence

Adolescents spend most of their daily time in school and performing school-related activities. Different aspects of their school experiences, such as school performance, psychological factors related to school, and structural factors, consistently impact adolescents' health and are likely to be intertwined with their sleep (i.e., quantity and quality, sleep disturbances). This systematic review aimed to comprehensively summarize the reciprocal and longitudinal associations between adolescents' sleep and multiple aspects of their school experience. Using multiple search strategies and applying a two-step selection process, 25 journal articles matched the eligibility criteria and were thus included in the review. The results highlighted the contribution of poor sleep quality and sleep disturbances in predicting longitudinal school experiences-related outcomes (i.e., decreasing school engagement and performance, and increasing school-related burnout, absenteeism, and bullying). At the same time, the results showed how experiences related to the school's psychological factors (e.g., high levels of school burnout and stressful environment) and structural characteristics (e.g., early school entrance time) affect youth sleep over time (i.e., decreasing sleep quality and quantity). These main findings provided novel insights into the bidirectional relationship between school experience and sleep health, highlighting the importance of more longitudinal research investigating all aspects of healthy sleep, including the size and direction of the association.

Mind-Body Integrative Health (MBIH) Interventions for Sleep among Adolescents: A Scoping Review of Implementation, Participation and Outcomes

Adolescents get insufficient sleep, adversely affecting health. Mind-body integrative health interventions for adolescents have been shown to reduce stress, a barrier to good sleep. This scoping review aimed to synthesize mind-body integrative health interventions for adolescents, how interventions were implemented, who was reached. A systematic search of four online databases was conducted. Randomized, quasi-experimental, and single-group designs with participants ages 10-24 years were included. Twelve studies covering 10 interventions using mindfulness, qigong, aromatherapy, or yoga were identified. Participants were predominantly female; only one study reported participants' race or ethnicity (81% non-Hispanic white). Most (n=6) interventions were delivered in groups, and half reported significant improvements in subjective sleep quality. Mindfulness-based stress reduction and mindfulness-based cognitive therapy were the most commonly used modalities, with reported impact on sleep outcomes measured objectively. The two interventions that found statistically significant, moderate improvements in objectively-measured sleep onset latency and sleep efficiency were of higher intensity and used mindfulness. Four interventions were self-directed; participants in these struggled with adherence; significant impacts on sleep were not found. While findings were mixed, stemming in part from the quality of the underlying studies, this review identified several promising features of interventions, including using mindfulness, ensuring sufficient intervention dose, and targeting interventions towards adolescents with poor sleep at baseline (rather than a general population of adolescents). The findings suggests that sleep interventions for adolescents may improve psychological well-being as an intermediate effect, as sleep improvements were observed mostly among participants with poor sleep quality or anxiety symptoms at baseline. This review identified several gaps in the literature. Despite documented racial and ethnic disparities in sleep quality among adolescents, published evidence of mind-body integrative health-based sleep interventions among Black and Latinx adolescents is lacking. None of the studies in this review assessed developmental stage or age differences, despite documented differences in sleep across age groups of adolescents. These two gaps in the evidence should be addressed in future intervention research.

Sleep timing and consistency are associated with the standardised test performance of Icelandic adolescents

Sleep has been shown to affect cognitive function in laboratory studies; however, its association to the academic performance of adolescents has largely been demonstrated using self-reported measures. Studies with objective measures of both sleep and academic performance are limited. The aim of the present study was to determine whether the free-living sleep quantity, quality, and timing of 15-year-old adolescents measured with wrist actiography are associated with their scores on national standardised examinations as an objective measure of academic achievement. We measured sleep with wrist actiography for 1 week in 253 (150 girls) Icelandic adolescents with a mean (SD) age of 15.9 (0.3) years. Multiple linear regression was used to assess associations between sleep parameters and combined standardised examination scores in mathematics, English, and Icelandic obtained from the Icelandic Directorate of Education. We found that students went to bed at 00:49 hours (± 51.8 min) and slept for a mean (SD) of 6.6 (0.7) hr/night, with a median (interquartile range) night-to-night variation in sleep duration of 1.2 (0.7) hr and an efficiency of 88.1 (5.3)%. Combined analyses adjusted for sex, demonstrated that both bedtime and night-to-night variability in total sleep time were negatively associated with the average score across all topics. Sex-specific associations did not indicate clear differences between boys and girls. These findings suggest that, in addition to appropriate sleep duration, public health guidance should also highlight the importance of early and consistent sleep schedules to academic achievement for both boys and girls.

Association between free-living sleep and memory and attention in healthy adolescents

In laboratory studies, imposed sleep restriction consistently reduces cognitive performance. However, the association between objectively measured, free-living sleep and cognitive function has not been studied in older adolescents. To address this gap, we measured one week of sleep with a wrist-worn GT3X+ actigraph in 160 adolescents (96 girls, 17.7 ± 0.3 years) followed by assessment of working memory with an n-back task and visual attention with a Posner cue-target task. Over the week, participants spent 7.1 ± 0.8 h/night in bed and slept 6.2 ± 0.8 h/night with 88.5 ± 4.8% efficiency and considerable intra-participant night-to-night variation, with a standard deviation in sleep duration of 1.2 ± 0.7 h. Sleep measures the night before cognitive testing were similar to weekly averages. Time in bed the night before cognitive testing was negatively associated with response times during the most challenging memory task (3-back; p = 0.005). However, sleep measures the night before did not correlate with performance on the attention task and weekly sleep parameters were not associated with either cognitive task. Our data suggests shorter acute free-living sleep may negatively impact difficult memory tasks, however the relationship between free-living sleep and cognitive task performance in healthy adolescents is less clear than that of laboratory findings, perhaps due to high night-to-night sleep variation.