Department of Health Promotion and Health Education, National Taiwan Normal University, Taipei, Taiwan.
Faculty of Sport Sciences, Waseda University, Tokorozawa, Japan.
Sci Rep. 2020 Dec 7;10(1):21344. doi: 10.1038/s41598-020-78072-0.
The positive association between the total duration of physical activity and performances of physical function may vary at different times of the day as circadian rhythm regulates individuals in response to external stimulations. We aimed to examine the association of timing-specific and overall moderate-to-vigorous physical activity (MVPA) with performances of physical function in older adults. A cross-sectional analysis was conducted among 118 older adults (mean age = 70.0 ± 5.0 years). We assessed and identified timing-specific (morning: 06:01-12:00; afternoon: 12:01-18:00; evening: 18:01-24:00) and overall MVPA using a triaxial accelerometer. Different measures of physical function were evaluated including handgrip strength (by grip dynamometer), gait speed (5-m walk test), basic functional mobility (timed up and go test), and lower limb strength (five times sit-to-stand test). Multivariate linear regression models adjusting for covariates were used to investigate the associations. Participants spent 25.0 (± 26.2) minutes in MVPA per day on average, half the time spent during the morning (47.7%), followed by during the afternoon (29.9%) and evening (21.6%). The time spent on overall MVPA was generally associated with better physical function performances. There was statistical evidence for the percentages of MVPA engagement during the morning [B = 0.214, 95% confidence interval (CI) 0.001 to 0.428] and afternoon (B = - 0.273, 95% CI - 0.518 to - 0.027) associated with basic functional mobility but with contrary directions; the percentage of MVPA engagement during the evening was associated with less time spent in gait speed performance (B = - 0.237, 95% CI - 0.468 to - 0.006). Our findings inform implications that the overall MVPA engagement was more important than timing-specific MVPA to older adults' physical function performances. Strategies for accumulating time of MVPA is more practical and effective than encouraging to engage MVPA in specific timing for the enhancement of functional ability and therefore prevent disability among older adults.
体力活动总时长与身体机能表现呈正相关，这可能因昼夜节律调节而在一天中的不同时间有所变化，该节律使个体对外界刺激做出反应。我们旨在研究特定时间和整体中等到剧烈体力活动（MVPA）与老年人身体机能表现的关联。我们对 118 名老年人（平均年龄 70.0 ± 5.0 岁）进行了横断面分析。我们使用三轴加速度计评估并确定了特定时间（早上：06:01-12:00；下午：12:01-18:00；晚上：18:01-24:00）和整体 MVPA。使用握力计评估了不同的身体机能指标，包括握力、步行速度（5 米步行测试）、基本功能移动性（计时起立行走测试）和下肢力量（五次坐站测试）。使用调整了协变量的多变量线性回归模型来研究关联。参与者平均每天进行 25.0（±26.2）分钟的 MVPA，其中一半时间在早上（47.7%），其次是下午（29.9%）和晚上（21.6%）。整体 MVPA 时间与身体机能表现较好相关。有统计证据表明，早上（B=0.214，95%置信区间[CI] 0.001-0.428）和下午（B=-0.273，95%CI -0.518-0.027）的 MVPA 参与率与基本功能移动性呈正相关，但方向相反；晚上的 MVPA 参与率与步行速度性能的时间呈负相关（B=-0.237，95%CI -0.468-0.006）。我们的研究结果表明，对于老年人的身体机能表现，整体 MVPA 的参与比特定时间的 MVPA 更为重要。为了增强功能能力，积累 MVPA 时间的策略比鼓励在特定时间进行 MVPA 更为实际和有效，从而防止老年人残疾。
