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This Article Full Text Full Text (PDF) All Versions of this Article: 295/2/H842    most recent 91426.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Soto, P. F. Articles by Gropler, R. J. Search for Related Content PubMed PubMed Citation Articles by Soto, P. F. Articles by Gropler, R. J.

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

¹Cardiovascular Division and ²Division of Geriatrics and Nutritional Sciences, Department of Medicine, ³Department of Radiological Sciences, Edward Mallinckrodt Institute of Radiology, and ⁴Department of Biostatistics, Washington University School of Medicine, St. Louis, Missouri

Submitted 12 December 2007 ; accepted in final form 16 June 2008

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 [¹⁵O]water, [¹¹C]acetate, [¹¹C]glucose, and [¹¹C]palmitate for the assessment of myocardial blood flow (MBF), myocardial O₂ consumption (MO₂), myocardial glucose utilization (MGU), and myocardial fatty acid utilization (MFAU), respectively, at rest and during dobutamine infusion (10 µg·kg^–1·min^–1). Measurements were repeated after 11 mo of EET. Maximal O₂ uptake (O_2max) increased (P = 0.005) after EET. MBF was unaffected by training, as was resting MO₂; however, posttraining dobutamine MO₂ 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.

aging; catecholamine; fatty acid; glucose; insulin resistance