早睡早起和增加睡眠时间会减少青少年久坐不动的行为，但不会减少其中等到剧烈的身体活动量。

Earlier bedtimes and more sleep displace sedentary behavior but not moderate-to-vigorous physical activity in adolescents.

机构信息

Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA; Department of Psychology, St. Louis Children's Hospital, St. Louis, Missouri, USA; Department of Clinical Pediatrics, Washington University, St. Louis, Missouri, USA.

Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA; Department of Psychology, Brigham Young University, Provo, Utah, USA.

出版信息

Sleep Health. 2022 Jun;8(3):270-276. doi: 10.1016/j.sleh.2022.01.003. Epub 2022 Apr 21.

DOI:10.1016/j.sleh.2022.01.003

PMID:35461788

Abstract

OBJECTIVES

Correlational models suggest increased cardiometabolic risk when sleep replaces moderate-to-vigorous (but not sedentary or light) physical activity. This study tested which activity ranges are impacted by experimentally altering adolescents' bedtime.

METHOD

Adolescents completed a 3-week within-subjects crossover experiment with 5 nights of late bedtimes and 5 nights early bedtimes (6.5- and 9.5-hours sleep opportunity, respectively). Experimental condition order was randomized. Waketimes were held constant throughout to mimic school start times. Sleep and physical activity occurred in the natural environments, with lab appointments following each 5-day condition. Waist-worn accelerometers measured physical activity and sedentary behavior. Wrist-worn actigraphs confirmed sleep condition adherence. Wilcoxon tests and linear mixed effects models compared waking activity levels between conditions and across time.

RESULTS

Ninety healthy adolescents (14-17 years) completed the study. When in the early (vs. late) bedtime condition, adolescents fell asleep 1.96 hours earlier (SD = 1.08, d = 1.82, p < .0001) and slept 1.49 hours more (SD = 1.01, d = 1.74, p < .0001). They spent 1.68 and 0.32 fewer hours in sedentary behavior (SD = 1.67, d = 1.0, p < .0001) and light physical activity (SD = 0.87, d = 0.37, p = .0005), respectively. This pattern was reflected in increased proportion of waking hours spent in sedentary and light activity. Absolute and proportion of moderate-to-vigorous physical activity did not differ between conditions (d = 0.02, p = .89; d = 0.14, p = .05, respectively).

CONCLUSIONS

Inducing earlier bedtimes (allowing for healthy sleep opportunity) did not affect moderate-to-vigorous physical activity. Alternatively, later bedtimes (allowing for ≤ 6.5 hours of sleep opportunity, mimicking common adolescent school night sleep) increased sedentary behavior. Results are reassuring for the benefits of earlier bedtimes.

摘要

目的

相关性模型表明，当睡眠取代中等至剧烈强度（而非久坐或低强度）的身体活动时，心血管代谢风险会增加。本研究通过实验改变青少年的就寝时间，来检验哪些活动范围会受到影响。

方法

青少年完成了一项为期 3 周的自身对照交叉实验，共包括 5 个晚睡夜和 5 个早睡夜（分别有 6.5-9.5 小时的睡眠时间）。实验条件的顺序是随机的。整个过程中保持清醒时间不变，以模拟学校的开始时间。睡眠和身体活动在自然环境中进行，在每个 5 天的条件后安排实验室预约。佩戴在腰部的加速度计测量身体活动和久坐行为，佩戴在手腕上的活动记录仪确认睡眠条件的遵守情况。使用 Wilcoxon 检验和线性混合效应模型比较条件之间和时间内的清醒活动水平。

结果

90 名健康青少年（14-17 岁）完成了这项研究。与晚睡相比，青少年在早睡时入睡时间提前 1.96 小时（SD=1.08，d=1.82，p<0.0001），睡眠时间增加 1.49 小时（SD=1.01，d=1.74，p<0.0001）。他们分别少进行 1.68 和 0.32 小时的久坐行为（SD=1.67，d=1.0，p<0.0001）和低强度身体活动（SD=0.87，d=0.37，p=0.0005）。这种模式反映在清醒时间中久坐和低强度活动所占比例的增加。条件之间的中等到剧烈强度身体活动的绝对量和比例没有差异（d=0.02，p=0.89；d=0.14，p=0.05）。