Endocrine Research Unit, Division of Endocrinology, Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA.
Department of Geriatrics, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China.
J Physiol. 2021 Jul;599(14):3581-3592. doi: 10.1113/JP281691. Epub 2021 Jun 11.
Healthy older adults exhibit lower cardiorespiratory fitness ( ) than young in the absence of any age-related difference in skeletal muscle mitochondrial capacity, suggesting central haemodynamics plays a larger role in age-related declines in . Total physical activity did not differ by age, but moderate-to-vigorous physical activity was lower in older compared to young adults. Moderate-to-vigorous physical activity is associated with and muscle oxidative capacity, but physical inactivity cannot entirely explain the age-related reduction in .
Declining fitness ( ) is a hallmark of ageing and believed to arise from decreased oxygen delivery and reduced muscle oxidative capacity. Physical activity is a modifiable lifestyle factor that is critical when evaluating the effects of age on parameters of fitness and energy metabolism. The objective was to evaluate the effects of age and sex on , muscle mitochondrial physiology, and physical activity in young and older adults. An additional objective was to assess the contribution of skeletal muscle oxidative capacity to age-related reductions in and determine if age-related variation in and muscle oxidative capacity could be explained on the basis of physical activity levels. In 23 young and 52 older men and women measurements were made of , mitochondrial physiology in permeabilized muscle fibres, and free-living physical activity by accelerometry. Regression analyses were used to evaluate associations between age and , mitochondrial function, and physical activity. Significant age-related reductions were observed for (P < 0.001), but not muscle mitochondrial capacity. Total daily step counts did not decrease with age, but older adults showed lower moderate-to-vigorous physical activity, which was associated with (R = 0.323, P < 0.001) and muscle oxidative capacity (R = 0.086, P = 0.011). After adjusting for sex and physical activity, age was negatively associated with but not muscle oxidative capacity. Healthy older adults exhibit lower but preserved mitochondrial capacity compared to young. Physical activity, particularly moderate-to-vigorous, is a key factor in observed age-related changes in fitness and muscle oxidative capacity, but cannot entirely explain the age-related reduction in .
在骨骼肌线粒体容量与年龄无关的情况下，健康的老年人的心肺功能（ ）低于年轻人，这表明中心血液动力学在与年龄相关的心肺功能下降中起着更大的作用。总体力活动不因年龄而异，但与年轻人相比，老年人的中高强度体力活动较低。中高强度体力活动与 和肌肉氧化能力有关，但身体活动不足不能完全解释与年龄相关的心肺功能下降。
体能下降（ ）是衰老的标志，据信这是由于氧气输送减少和肌肉氧化能力降低所致。体力活动是一个可改变的生活方式因素，对于评估年龄对体能和能量代谢参数的影响至关重要。本研究旨在评估年龄和性别对年轻人和老年人的心肺功能、肌肉线粒体生理学和体力活动的影响。另一个目的是评估骨骼肌氧化能力对心肺功能下降的贡献，并确定与年龄相关的心肺功能和肌肉氧化能力的变化是否可以根据体力活动水平来解释。在 23 名年轻和 52 名年老的男性和女性中，通过加速度计测量心肺功能、肌肉线粒体生理学和自由生活体力活动。回归分析用于评估年龄与心肺功能、线粒体功能和体力活动之间的关系。结果显示，心肺功能（ ）显著降低（P<0.001），但肌肉线粒体容量没有降低。总的日常步数没有随年龄而减少，但老年人的中高强度体力活动较低，这与心肺功能（R = 0.323，P<0.001）和肌肉氧化能力（R = 0.086，P = 0.011）有关。在校正性别和体力活动后，年龄与心肺功能呈负相关，但与肌肉氧化能力无关。与年轻人相比，健康的老年人的心肺功能较低，但线粒体容量保持不变。体力活动，尤其是中高强度体力活动，是观察到的与年龄相关的体能和肌肉氧化能力变化的关键因素，但不能完全解释心肺功能与年龄相关的下降。
