National Institute on Aging, National Institutes of Health, Baltimore, Maryland.
Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
J Gerontol A Biol Sci Med Sci. 2020 Nov 13;75(12):2262-2268. doi: 10.1093/gerona/glaa071.
Resting metabolic rate (RMR) tends to decline with aging. The age-trajectory of decline in RMR is similar to changes that occur in muscle mass, muscle strength, and fitness, but while the decline in these phenotypes has been related to changes of mitochondrial function and oxidative capacity, whether lower RMR is associated with poorer mitochondrial oxidative capacity is unknown. In 619 participants of the Baltimore Longitudinal Study of Aging, we analyzed the cross-sectional association between RMR (kcal/day), assessed by indirect calorimetry, and skeletal muscle maximal oxidative phosphorylation capacity, assessed as postexercise phosphocreatine recovery time constant (τ PCr), by phosphorous magnetic resonance spectroscopy. Linear regression models were used to evaluate the relationship between τ PCr and RMR, adjusting for potential confounders. Independent of age, sex, lean body mass, muscle density, and fat mass, higher RMR was significantly associated with shorter τ PCr, indicating greater mitochondrial oxidative capacity. Higher RMR is associated with a higher mitochondrial oxidative capacity in skeletal muscle. This association may reflect a relationship between better muscle quality and greater mitochondrial health.
静息代谢率（RMR）往往随着年龄的增长而下降。RMR 下降的年龄轨迹与肌肉质量、肌肉力量和健康状况的变化相似，但这些表型的下降与线粒体功能和氧化能力的变化有关，而较低的 RMR 是否与较差的线粒体氧化能力有关尚不清楚。在巴尔的摩老龄化纵向研究的 619 名参与者中，我们通过磷磁共振波谱分析，分析了通过间接热量测定法评估的 RMR（千卡/天）与骨骼肌最大氧化磷酸化能力（通过运动后磷酸肌酸恢复时间常数 τPCr 评估）之间的横断面关联。线性回归模型用于评估 τPCr 和 RMR 之间的关系，调整了潜在的混杂因素。独立于年龄、性别、瘦体重、肌肉密度和脂肪质量，较高的 RMR 与较短的 τPCr 显著相关，表明线粒体氧化能力更高。较高的 RMR 与骨骼肌更高的线粒体氧化能力相关。这种关联可能反映了更好的肌肉质量和更大的线粒体健康之间的关系。
