Hamer Mark, Stamatakis Emmanuel, Steptoe Andrew
1Physical Activity Research Group, Department of Epidemiology and Public Health, University College London, London, UNITED KINGDOM; 2Psychobiology Group, Department of Epidemiology and Public Health, University College London, London, UNITED KINGDOM; 3Exercise and Sport Sciences, Faculty of Health Sciences, University of Sydney, Sydney, AUSTRALIA; and 4Charles Perkins Centre, University of Sydney, Sydney, AUSTRALIA.
Med Sci Sports Exerc. 2014 Oct;46(10):1946-50. doi: 10.1249/MSS.0000000000000317.
The detrimental effects of sedentary time on health may act by replacing time spent in physical activities. The aim of this study was to examine cross-sectional associations between objectively assessed sedentary and physical activity domains and cardiometabolic risk factors using a novel isotemporal substitution paradigm.
Participants were 445 healthy men and women (mean age, 66 ± 6 yr), without history or objective signs of cardiovascular disease, drawn from the Whitehall II epidemiological cohort. Physical activity was objectively measured using accelerometers (ActiGraph GT3X) worn around the waist during waking hours for 4-7 consecutive days. We examined the effects of replacing sedentary time with light activity or moderate-to-vigorous physical activity (MVPA) on a range of risk factors (HDL cholesterol, triglycerides, HbA1c, and body mass index) using an isotemporal substitution paradigm.
In partition models, where the time in each of the intensity categories was held constant, only MVPA remained associated with risk factors. In isotemporal substitution models that held total (wear) time constant, replacing 10-min sedentary time with an equal amount of MVPA was associated with favorable effects in all risk factors, including HbA1c (B = -0.023; 95% confidence interval (CI), -0.043 to -0.002), BMI (B = -0.39; 95% CI, -0.54 to -0.24), HDL cholesterol (B = 0.037; 95% CI, 0.021-0.054), and triglycerides (B = -0.035; 95% CI, -0.061 to -0.009).
The associations between sedentary behavior and cardiometabolic risk may be dependent on the types of activities that are displaced by sedentary time.
久坐时间对健康的有害影响可能是通过取代体育活动时间来起作用的。本研究的目的是使用一种新的等时替代范式，研究客观评估的久坐和体育活动领域与心血管代谢危险因素之间的横断面关联。
参与者为445名健康男性和女性（平均年龄66±6岁），无心血管疾病史或客观体征，来自怀特霍尔二世流行病学队列。使用加速度计（ActiGraph GT3X）在清醒时间连续4至7天佩戴在腰部，客观测量身体活动。我们使用等时替代范式，研究用轻度活动或中度至剧烈身体活动（MVPA）替代久坐时间对一系列危险因素（高密度脂蛋白胆固醇、甘油三酯、糖化血红蛋白和体重指数）的影响。
在分区模型中，每个强度类别的时间保持不变，只有MVPA仍与危险因素相关。在总（佩戴）时间保持不变的等时替代模型中，用等量的MVPA替代10分钟的久坐时间与所有危险因素的有利影响相关，包括糖化血红蛋白（B = -0.023；95%置信区间（CI），-0.043至-0.002）、体重指数（B = -0.39；95%CI，-0.54至-0.24）、高密度脂蛋白胆固醇（B = 0.037；95%CI，0.021 - 0.054）和甘油三酯（B = -0.035；95%CI，-0.061至-0.009）。
久坐行为与心血管代谢风险之间的关联可能取决于被久坐时间取代的活动类型。
