Objective

Physical activity, sedentary behavior, and sleep are associated with mental health in adolescents. Mental health may depend not only on the amount of time spent in a specific activity, but also on the activity it displaces. The aim of this study was to examine the impact of reallocating 15 min of time spent in one health behavior with 15 min in another on adolescent mental health.

Methods

Cross-sectional data from the students participating in the COMPASS Study (2018–2019) were analyzed (N = 46,413). Participants self-reported the amount of time they spent engaged in moderate-to-vigorous physical activity (MVPA), doing homework and using screens, and their sleep duration on average each day, depressive symptoms, anxiety, and flourishing. Data were analyzed using isotemporal substitution modeling.

Results

Among adolescents getting less than the recommended amount of sleep, replacing any behavior with sleep was generally associated with better mental health outcomes. Conversely, among adolescents getting adequate sleep, the findings did not support replacing other behaviors with sleep with the exception of screen time. Replacing homework and MVPA with sleep was associated with less flourishing regardless of sleep duration.

Conclusions

Replacing screen time with any behavior may be better for mental health outcomes. Results provide further support for the critical role of sleep in promoting healthy development during adolescence, though more sleep than is recommended may confer little benefit for mental health. The findings demonstrate that mental health benefits may be obtainable at intervals as short as 15 min.

中文翻译：

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重新分配身体活动，久坐行为和睡眠对青少年心理健康的影响

目的

身体活动，久坐行为和睡眠与青少年的心理健康有关。心理健康不仅取决于特定活动花费的时间，还取决于它取代的活动。这项研究的目的是检验重新分配一种健康行为的15分钟时间和另一种15分钟的时间对青少年心理健康的影响。

方法

分析了参加COMPASS研究（2018-2019）的学生的横截面数据（N  = 46,413）。参与者自我报告了他们从事中度至剧烈运动（MVPA），做家庭作业和使用屏幕的时间，以及他们平均每天的睡眠时间，抑郁症状，焦虑和情绪旺盛。使用等时替代模型分析数据。

结果

在青少年的睡眠时间少于建议的睡眠量中，以睡眠代替任何行为通常可以改善心理健康状况。相反，在睡眠充足的青少年中，研究结果不支持用除筛查时间以外的睡眠来代替其他行为。无论睡眠时间长短，用睡眠代替家庭作业和MVPA都可以减少繁华。

结论

用任何行为代替检查时间可能对心理健康结果更好。结果为睡眠在青春期促进健康发展中的关键作用提供了进一步的支持，尽管睡眠时间多于建议的时间可能对精神健康无济于事。研究结果表明，精神健康益处可在短至15分钟的间隔内获得。