Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
Center on Aging and Health, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, Maryland.
J Gerontol A Biol Sci Med Sci. 2019 Mar 14;74(4):560-567. doi: 10.1093/gerona/gly243.
With aging, daily physical activity (PA) becomes less frequent and more fragmented. Accumulation patterns of daily PA-including transitions from active-to-sedentary behaviors-may provide important insights into functional status in older, less active populations.
Participants of the Baltimore Longitudinal Study of Aging (n = 680, 50% male, aged 27-94 years) completed a clinical assessment and wore an Actiheart accelerometer. Transitions between active and sedentary states were modeled as a probability (Active-to-Sedentary Transition Probability [ASTP]) defined as the reciprocal of the average PA bout duration. Cross-sectional associations between ASTP and gait speed (m/s), fatigability (rating-of-perceived-exertion [RPE]), 400 m time (seconds), and expanded short physical performance battery score were modeled using linear and logistic regression, adjusted for chronic conditions. Further analyses explored the utility of ASTP over-and-above total daily PA.
In continuous models, each 0.10-unit higher ASTP was associated slower gait (β = -0.06 m/s, SE = 0.01), higher fatigability (β = 0.60 RPE, SE = 0.12), slower 400 m time (β = 16.31 s, SE = 2.70), and lower functioning (β = -0.13 expanded short physical performance battery score, SE = 0.03; p < .001). In categorical analyses, those in the highest tertile of ASTP were >2 times more likely to have high fatigability (rating of perceived exertion ≥10), slow 400 m time (>300 seconds) and reduced functional performance (expanded short physical performance battery score < 3.07) than those in the lowest tertile (p < .01). Further analyses demonstrated ASTP provided additional insight into functional outcomes beyond total daily PA.
Fragmented daily PA-as measured by ASTP-is strongly linked with measures of health and functional status and may identify those at risk of high fatigability and reduced functional performance over and above traditional PA metrics.
随着年龄的增长，日常体力活动（PA）变得不那么频繁，也更加分散。日常 PA 的积累模式，包括从活跃到久坐行为的转变，可能为年龄较大、活动较少的人群的功能状态提供重要的见解。
巴尔的摩纵向衰老研究（BLS）的参与者（n = 680，50%为男性，年龄 27-94 岁）完成了临床评估并佩戴了 Actiheart 加速度计。将活跃状态和久坐状态之间的转变建模为一个概率（Active-to-Sedentary Transition Probability [ASTP]），定义为平均 PA 爆发持续时间的倒数。使用线性和逻辑回归模型，根据慢性疾病调整，对 ASTP 与步态速度（m/s）、疲劳性（感知用力等级[RPE]）、400 米时间（秒）和扩展简短体能表现电池评分之间的横断面关联进行建模。进一步的分析探讨了 ASTP 相对于总日常 PA 的效用。
在连续模型中，ASTP 每增加 0.10 个单位，与较慢的步态（β = -0.06 m/s，SE = 0.01）、更高的疲劳性（β = 0.60 RPE，SE = 0.12）、较慢的 400 米时间（β = 16.31 s，SE = 2.70）和较低的功能（β = -0.13 扩展简短体能表现电池评分，SE = 0.03；p <.001）相关。在分类分析中，ASTP 最高三分位的人比最低三分位的人更有可能出现高疲劳性（感知用力等级≥10）、400 米时间较慢（>300 秒）和功能表现降低（扩展简短体能表现电池评分<3.07）（p <.01）。进一步的分析表明，ASTP 提供了关于健康和功能状态的额外信息，超越了传统的 PA 指标，这些信息可能识别出那些容易疲劳和功能表现降低的人。
日常 PA 的碎片化（通过 ASTP 测量）与健康和功能状态的衡量指标密切相关，并且可能识别出那些比传统 PA 指标更容易疲劳和功能表现降低的人。
