Exercise training impacts the myocardial metabolism of older individuals in a gender-specific manner

Abstract

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.

Sex differences in physiological cardiac hypertrophy are associated with exercise-mediated changes in energy substrate availability

“…With the use of cardiac PET analysis, myocardial glucose and fatty acid utilization was studied in 12 healthy older individuals (6 men/6 women) before and after an 11-mo endurance exercise training period (36). In consonance with our data, the authors found increased posttraining plasma FFA levels in women compared with men.…”

“…Along this line, Soto et al (36) recently investigated these processes in humans. With the use of cardiac PET analysis, myocardial glucose and fatty acid utilization was studied in 12 healthy older individuals (6 men/6 women) before and after an 11-mo endurance exercise training period (36).…”

‘SeXX’ matters: In the myocardium of patients with type 1 diabetes

“…[6][7][8] In several studies of healthy and obese individuals, women tended to have higher myocardial blood flow than men. [7][8][9] This is similar to the results from the current study by Duvernoy et al 5 Myocardial blood flow was also higher in women with type 2 diabetes compared with men with the same disease. This is consistent with prior literature, which has been fairly consistent in demonstrating that oxygen consumption is generally higher in womennormal, obese, and with type 2 diabetes mellitus, than in comparable groups of men.…”

Sex and Sex Hormone–Dependent Cardiovascular Stress Responses

“…4 Increased posttraining plasma free fatty acid (FFA) levels were found in women compared with men. More importantly, this was accompanied with increased catecholamine-induced cardiac fatty acid use posttraining in women but not in men, suggesting a predominance of lipids as the female cardiac fuel during exercise.…”