Soto Pablo F, Herrero Pilar, Schechtman Kenneth B, Waggoner Alan D, Baumstark Jeffrey M, Ehsani Ali A, Gropler Robert J
Cardiovascular Div., Washington Univ. School of Medicine, Campus Box 8225, 660 S. Euclid Ave., St. Louis, MO 63110, USA.
Am J Physiol Heart Circ Physiol. 2008 Aug;295(2):H842-50. doi: 10.1152/ajpheart.91426.2007. Epub 2008 Jun 20.
Aging is associated with decreases in aerobic capacity, cardiac function, and insulin sensitivity as well as alterations in myocardial substrate metabolism. Endurance exercise training (EET) improves cardiac function in a gender-specific manner, and EET has been shown to improve whole body glucose tolerance, but its effects on myocardial metabolism are unclear. Accordingly, we studied the effect of EET on myocardial substrate metabolism in older men and women. Twelve healthy older individuals (age: 60-75 yr; 6 men and 6 women) underwent PET with [(15)O]water, [(11)C]acetate, [(11)C]glucose, and [(11)C]palmitate for the assessment of myocardial blood flow (MBF), myocardial O(2) consumption (MVo(2)), myocardial glucose utilization (MGU), and myocardial fatty acid utilization (MFAU), respectively, at rest and during dobutamine infusion (10 microg.kg(-1).min(-1)). Measurements were repeated after 11 mo of EET. Maximal O(2) uptake (Vo(2max)) increased (P = 0.005) after EET. MBF was unaffected by training, as was resting MVo(2); however, posttraining dobutamine MVo(2) was significantly higher (P = 0.05), as was MGU (P < 0.04). Although overall dobutamine MFAU was unchanged, posttraining dobutamine MFAU increased in women (P = 0.01) but decreased in men (P = 0.03). Thus, EET in older individuals improves the catecholamine response of myocardial glucose metabolism. Moreover, gender differences exist in the myocardial fatty acid metabolic response to training. These findings suggest a role for altered myocardial substrate metabolism in modulating the cardiovascular benefits of EET in older individuals.
衰老与有氧能力、心脏功能、胰岛素敏感性下降以及心肌底物代谢改变有关。耐力运动训练（EET）以性别特异性方式改善心脏功能，并且已证明EET可改善全身葡萄糖耐量，但其对心肌代谢的影响尚不清楚。因此，我们研究了EET对老年男性和女性心肌底物代谢的影响。12名健康老年人（年龄：60 - 75岁；6名男性和6名女性）接受了用[（15）O]水、[（11）C]乙酸盐、[（11）C]葡萄糖和[（11）C]棕榈酸盐进行的正电子发射断层扫描（PET），分别用于评估静息状态和多巴酚丁胺输注（10μg·kg（-1）·min（-1））期间的心肌血流量（MBF）、心肌氧消耗（MVo（2））、心肌葡萄糖利用（MGU）和心肌脂肪酸利用（MFAU）。在EET进行11个月后重复测量。EET后最大摄氧量（Vo（2max））增加（P = 0.005）。MBF不受训练影响，静息MVo（2）也不受影响；然而，训练后多巴酚丁胺刺激的MVo（2）显著更高（P = 0.05），MGU也是如此（P < 0.04）。虽然总体多巴酚丁胺刺激的MFAU没有变化，但训练后多巴酚丁胺刺激的MFAU在女性中增加（P = 0.01）而在男性中减少（P = 0.03）。因此，老年人的EET改善了心肌葡萄糖代谢的儿茶酚胺反应。此外，在心肌脂肪酸代谢对训练的反应中存在性别差异。这些发现表明，心肌底物代谢改变在调节老年人EET的心血管益处中起作用。
