Poehlman E T, Arciero P J, Goran M I
Department of Medicine, University of Maryland, Baltimore.
Exerc Sport Sci Rev. 1994;22:251-84.
In summary, data suggest that the decline in RMR with advancing age is primarily related to the decline in fat-free mass. However, in addition to the erosion of fat-free mass, other factors such as Na-K pump activity, fat mass, maximal aerobic power, and menopausal status are important determinants influencing the decline in RMR in older individuals. Second, we provide revised prediction equations for RMR that are both gender- and sex-specific and use easily measured variables to facilitate their use in clinical and field settings. Third, preliminary studies suggest that older individuals may have a reduced energy expenditure following meal ingestion, although this is not a universal finding among investigators. Furthermore, several studies suggest that physically active older men exhibit higher thermic responses to a meal than sedentary older men. Data on total energy expenditure in free-living elderly persons are sparse. However, the available data suggest that there is large variation in total energy expenditure in the elderly population, caused primarily by differences in physical activity. The heterogeneity in physical activity makes estimation of individual energy requirements difficult. However, preliminary studies have suggested that measurement of VO2max and other activity indices may be useful markers for estimating energy requirements on an individual basis. Furthermore, attempting to "normalize" total energy expenditure in the elderly by prescribing physical activity is not as straightforward as it seems, due to exercise-induced compensatory reductions in physical activity during the remainder of the day. Levels of insulin-like growth factor-1 decline with advancing age. Preliminary evidence from cross-sectional and exercise intervention studies suggest that the lower serum levels of IGF-1 in older individuals may be partially due to diminished physical activity. Aging is associated with an increase in fasting levels of norepinephrine, primarily influenced by an elevated rate of norepinephrine into circulation; however, the clinical significance of the elevated sympathetic tone is unclear. Endurance training in older individuals has been found to increase basal levels of norepinephrine appearance into circulation, and this has been associated with an increased RMR and enhanced fat oxidation. Optimal exercise interventions need to be identified for the elderly, which maximally increase daily energy expenditure and offset metabolic deterioration with advancing age.
总之，数据表明静息代谢率（RMR）随年龄增长而下降主要与去脂体重的减少有关。然而，除了去脂体重的减少外，其他因素如钠钾泵活性、脂肪量、最大有氧能力和绝经状态也是影响老年人RMR下降的重要决定因素。其次，我们提供了针对RMR的修订预测方程，这些方程具有性别特异性，并且使用易于测量的变量，以便于在临床和现场环境中使用。第三，初步研究表明，老年人进食后能量消耗可能会减少，尽管并非所有研究者都有这一发现。此外，多项研究表明，身体活跃的老年男性对一餐的热反应高于久坐不动的老年男性。关于自由生活的老年人总能量消耗的数据稀少。然而，现有数据表明，老年人群的总能量消耗存在很大差异，主要是由身体活动的差异所致。身体活动的异质性使得估计个体能量需求变得困难。然而，初步研究表明，测量最大摄氧量（VO2max）和其他活动指标可能是个体基础上估计能量需求的有用标志物。此外，由于运动导致当天其余时间身体活动的代偿性减少，试图通过规定身体活动来“规范”老年人的总能量消耗并不像看起来那么简单。胰岛素样生长因子-1水平随年龄增长而下降。横断面研究和运动干预研究的初步证据表明，老年人血清IGF-1水平较低可能部分归因于身体活动减少。衰老与去甲肾上腺素空腹水平升高有关，主要受去甲肾上腺素进入循环速率升高的影响；然而，交感神经张力升高的临床意义尚不清楚。已发现对老年人进行耐力训练可增加去甲肾上腺素进入循环的基础水平，这与静息代谢率增加和脂肪氧化增强有关。需要为老年人确定最佳运动干预措施，以最大程度地增加每日能量消耗并抵消随着年龄增长而出现的代谢恶化。
