Poehlman E T, Danforth E
Department of Medicine, College of Medicine, University of Vermont, Burlington 05405.
Am J Physiol. 1991 Aug;261(2 Pt 1):E233-9. doi: 10.1152/ajpendo.1991.261.2.E233.
We examined the effects of an 8-wk endurance training program (cycling exercise) on resting metabolic rate (RMR) and norepinephrine (NE) kinetics in 19 older persons (64 +/- 1.6 yr). Before and after training, RMR, NE kinetics, maximal O2 consumption (VO2max), body composition, supine blood pressure, estimated energy intake, and fasting levels of glucose, insulin, and thyroid hormones were measured. RMR increased 10% after training. Resting concentrations of NE increased 24% after training due to a 21% increase in NE appearance rate and no change in NE clearance. Training increased VO2max (14%; P less than 0.01) and energy intake (12%; P less than 0.01), whereas no change was noted in body composition. Supine blood pressure and plasma glucose were lower after training, whereas no change was noted in fasting levels of plasma insulin. The increase in RMR was associated with a higher rate of NE appearance (r = 0.57; P = 0.05) and with increase in energy intake (r = 0.56; P = 0.05). Together these two factors accounted for 49% (r2) of the variation of the change in RMR. Changes in blood pressure were not associated with changes in NE kinetics. We conclude that endurance training increases total energy expenditure in older individuals by the direct energy cost of physical activity and by elevating RMR. This increase is partially mediated by an increased NE appearance rate and increased food intake in healthy older individuals.
我们研究了一项为期8周的耐力训练计划（骑自行车运动）对19名老年人（64±1.6岁）静息代谢率（RMR）和去甲肾上腺素（NE）动力学的影响。在训练前后，测量了RMR、NE动力学、最大耗氧量（VO2max）、身体成分、仰卧位血压、估计能量摄入量以及葡萄糖、胰岛素和甲状腺激素的空腹水平。训练后RMR增加了10%。训练后NE的静息浓度增加了24%，这是由于NE出现率增加了21%，而NE清除率没有变化。训练使VO2max增加（14%；P<0.01），能量摄入量增加（12%；P<0.01），而身体成分没有变化。训练后仰卧位血压和血浆葡萄糖较低，而血浆胰岛素空腹水平没有变化。RMR的增加与较高的NE出现率（r = 0.57；P = 0.05）以及能量摄入量的增加（r = 0.56；P = 0.05）相关。这两个因素共同解释了RMR变化的49%（r2）。血压变化与NE动力学变化无关。我们得出结论，耐力训练通过体力活动的直接能量消耗和提高RMR来增加老年人的总能量消耗。这种增加部分是由健康老年人中NE出现率的增加和食物摄入量的增加介导的。
