Lakatta E G
Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, Baltimore, MD 21224.
Aging (Milano). 1994 Aug;6(4):213-23. doi: 10.1007/BF03324244.
In healthy normotensive individuals who have been rigorously screened to exclude coronary disease, the cardiovascular reserve capacity decreases with aging. A reduction in the maximum aerobic capacity is accompanied by a reduction in the maximum heart rate. Stroke volume during vigorous exercise in the upright position does not decline with aging in healthy individuals, because the left ventricular end-diastolic volume dilates more in older than in younger individuals; however, the reduction in left ventricular end-systolic volume that occurs during exercise is blunted in older individuals, resulting in a lesser increase in the left ventricular ejection fraction. This pattern of altered cardiac reserve resembles that caused by beta-adrenergic blockade, and substantial evidence indicates that the efficacy of the beta-adrenergic post synaptic response of cardiovascular tissues declines with aging. Changes in cardiac structure, e.g., enlargement of cardiac myocytes leading to a moderate heart wall thickening, and changes in vascular properties, e.g., aortic wall thickening and increased stiffness, also likely have a role in the reduction in left ventricular reserve in older individuals. Chronic exercise conditioning in older individuals increases aerobic capacity, decreases arterial stiffness and left ventricular function. The exercise heart rate deficit that occurs with aging, however, is not affected by physical conditioning.
在经过严格筛查以排除冠心病的健康血压正常个体中，心血管储备能力会随着年龄增长而下降。最大有氧能力的降低伴随着最大心率的降低。健康个体在直立位剧烈运动时的每搏输出量不会随年龄增长而下降，因为老年个体的左心室舒张末期容积比年轻个体扩张得更多；然而，老年个体运动时左心室收缩末期容积的减少变得不明显，导致左心室射血分数的增加幅度较小。这种心脏储备改变的模式类似于β-肾上腺素能阻滞所引起的模式，大量证据表明心血管组织的β-肾上腺素能突触后反应的效能会随着年龄增长而下降。心脏结构的变化，例如心肌细胞增大导致心脏壁适度增厚，以及血管特性的变化，例如主动脉壁增厚和僵硬度增加，也可能在老年个体左心室储备减少中起作用。老年个体进行长期运动训练可增加有氧能力、降低动脉僵硬度和改善左心室功能。然而，随着年龄增长出现的运动心率不足不受体能训练的影响。
