Miatke Aaron, Olds Tim, Maher Carol, Fraysse Francois, Dumuid Dorothea
Alliance for Research in Exercise, Nutrition and Activity (ARENA), Allied Health and Human Performance, University of South Australia, Adelaide, 5000, Australia.
Centre for Adolescent Health, Murdoch Children's Research Institute, Parkville, 3052, Australia.
J Act Sedentary Sleep Behav. 2025 Jul 11;4(1):11. doi: 10.1186/s44167-025-00082-y.
Time spent in sleep, sedentary behaviour (SB), light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) all impact child health. The aim of this study was to investigate cross-sectional and longitudinal associations between time use and adiposity and cardio-respiratory fitness (CRF) in school-aged children.
Cross-sectional (n = 281) and longitudinal (n = 305) data were used from the Life on Holidays study with assessments over three time periods (two consecutive school years, and the interleaving summer holiday period). 24-h time use was measured using wrist-worn accelerometers. Adiposity was assessed as BMI z-score from measured weight and height, using World Health Organization reference data, and from body fat percentage (%BF) measured via bioelectrical impedance. CRF was operationalised as estimated VOmax from the 20-m shuttle run test. Compositional data analysis in conjunction with linear mixed-effects models was used to investigate the associations between time-use composition and outcomes after controlling for covariates. Cross-sectional models used baseline measures, and longitudinal models used rates of change in each outcome. Sensitivity analyses explored relationships for moderate physical activity (MPA) and vigorous physical activity (VPA) separately.
In cross-sectional analyses, time spent in MVPA was favourably associated with all adiposity and fitness outcomes (all p < 0.01) whereas time in LPA was unfavourably associated with all outcomes (all p < 0.01). Sleep was favourably associated with %BF, whereas SB was unfavourably associated (both p = 0.02). In longitudinal models, only MVPA was significantly associated with any of the three outcomes. 30 min/day more time spent in MVPA was associated with a decrease in %BF rate of change (-0.60 to -0.48) when time was reallocated from LPA or SB, and with an increase in VOmax (+ 0.89 to + 1.01) when time was reallocated from any other behaviour. Sensitivity analyses showed VPA was significantly associated with changes in %BF and VOmax.
All behaviours displayed cross-sectional associations with adiposity and CRF. However, only MVPA (and in particular VPA) was significantly associated with changes in %BF or VOmax in longitudinal models. Future efforts should focus on increasing participation in MVPA with school-aged children to see the most benefit to health.
睡眠时间、久坐行为（SB）、轻度身体活动（LPA）和中度至剧烈身体活动（MVPA）均会影响儿童健康。本研究旨在调查学龄儿童时间利用与肥胖及心肺适能（CRF）之间的横断面和纵向关联。
采用“假期生活”研究中的横断面数据（n = 281）和纵向数据（n = 305），评估在三个时间段（连续两个学年以及其间的暑假）进行。使用腕戴式加速度计测量24小时的时间利用情况。肥胖程度通过体重和身高测量的BMI z评分（使用世界卫生组织参考数据）以及通过生物电阻抗测量的体脂百分比（%BF）来评估。CRF通过20米穿梭跑测试估计的最大摄氧量来衡量。在控制协变量后，结合线性混合效应模型使用成分数据分析来研究时间利用构成与结果之间的关联。横断面模型使用基线测量值，纵向模型使用每个结果的变化率。敏感性分析分别探讨了中度身体活动（MPA）和剧烈身体活动（VPA）的关系。
在横断面分析中，MVPA时间与所有肥胖和适能结果呈有利关联（所有p < 0.01），而LPA时间与所有结果呈不利关联（所有p < 0.01）。睡眠与%BF呈有利关联，但SB与之呈不利关联（两者p = 0.02）。在纵向模型中，只有MVPA与这三个结果中的任何一个显著相关。当时间从LPA或SB重新分配时，每天多花30分钟在MVPA上与%BF变化率的降低（-0.60至-0.48）相关，当时间从任何其他行为重新分配时，与最大摄氧量的增加（+0.89至+1.01）相关。敏感性分析表明，VPA与%BF和最大摄氧量的变化显著相关。
所有行为均显示出与肥胖和CRF的横断面关联。然而，在纵向模型中，只有MVPA（尤其是VPA）与%BF或最大摄氧量的变化显著相关。未来的努力应集中在增加学龄儿童对MVPA的参与度，以实现对健康的最大益处。
