School of Public Health, The University of Queensland, Herston Rd, Herston, Brisbane, Queensland, 4006, Australia.
Baker IDI Heart and Diabetes Institute, Melbourne, Australia.
Osteoporos Int. 2018 Jun;29(6):1341-1350. doi: 10.1007/s00198-018-4428-6. Epub 2018 Feb 26.
The mechanisms through which excessive sitting time impacts health are important to understand. This study found that each hour of sitting per day was not associated with physical function, although associations with poor body composition were observed. Reducing sitting time for improved weight management in older adults needs further exploration.
To examine the association of sitting time and breaks in sitting time with muscle mass, strength, function, and inflammation in older Australians.
Data from the thigh-worn activPAL3™ monitor (7-day continuous wear) was used to derive time spent sitting (hours) and total number of sit-stand transitions per day. Body composition (dual energy X-ray absorptiometry), lower-body muscle strength, function (timed up-and-go [TUG], 4-m gait speed, four square step test, 30-second sit-to-stand), and serum inflammatory markers (interleukin-[IL-6], IL-8, IL-10, tumor necrosis factor-alpha [TNF-α], and adiponectin) were measured. Multiple regression analyses, adjusted for age, sex, ethnicity, education, employment status, marital status, number of prescription medications, smoking status, vitamin D, and stepping time, were used to assess the associations.
Data from 123 community-dwelling older adults (aged 65-84 years, 63% female) were used. Total daily sitting time was associated with lower percentage lean mass (β [95%CI], - 1.70% [- 2.30, - 1.10]) and higher total body fat mass (2.92 kg [1.94, 3.30]). More frequent breaks in sitting time were associated with a 45% reduced risk of having pre-sarcopenia (OR = 0.55; 95% CI 0.34, 0.91; model 1), defined as appendicular lean mass divided by BMI. No significant associations were observed for sitting time or breaks in sitting with measures of muscle strength, function, or inflammation.
In older community-dwelling adults, greater sitting time was associated with a lower percentage lean mass, while more frequent breaks in sitting time were associated with lower odds of having pre-sarcopenia. This suggests that reducing sedentary time and introducing frequent breaks in sedentary time may be beneficial for improving body composition in healthy older adults.
研究每天坐的时间与肌肉质量、力量、功能和炎症之间的关系。
使用 thigh-worn activPAL3™ 监测器（连续佩戴 7 天）获取每天的坐姿时间（小时）和总坐站转换次数。使用双能 X 射线吸收法（DXA）测量身体成分，用计时起立行走测试（TUG）、4 米步行速度、四方步测试和 30 秒坐立测试评估下肢肌肉力量和功能，用酶联免疫吸附法（ELISA）检测血清炎症标志物（白细胞介素-6 [IL-6]、IL-8、IL-10、肿瘤坏死因子-α [TNF-α]和脂联素）。调整年龄、性别、种族、教育程度、就业状况、婚姻状况、处方药数量、吸烟状况、维生素 D 和踏步数后，使用多元回归分析评估相关性。
纳入了 123 名社区居住的老年人（年龄 65-84 岁，63%为女性）的数据。每天的总坐姿时间与较低的瘦体重百分比（β[95%CI]，-1.70%[-2.30，-1.10%]）和较高的总体脂肪量相关。更频繁的坐姿中断与较低的肌少症前期风险相关（OR=0.55；95%CI 0.34，0.91；模型 1），肌少症前期定义为四肢骨骼肌质量与 BMI 的比值。坐姿时间或坐姿中断与肌肉力量、功能或炎症标志物均无显著相关性。
在社区居住的老年人中，更多的坐姿时间与较低的瘦体重百分比相关，而更频繁的坐姿中断与较低的肌少症前期风险相关。这表明减少久坐时间并引入频繁的坐姿中断可能有益于改善健康老年人的身体成分。
