Cardiovascular and Skeletal Muscle Health with Lifelong Exercise
Abstract
The purpose of this study was to examine the effects of lifelong aerobic exercise (LLE) on VO2max and skeletal muscle metabolic fitness in trained females (n=7, 72±2y) and males (n=21, 74±1y), and compare them to old healthy non-exercisers (OH; females: n=10, 75±1y; males: n=10, 75±1y), and young exercisers (YE; females: n=10, 25±1y; males: n=10, 25±1y). LLE males were further subdivided based on intensity of lifelong exercise and competitive status into performance (LLE-P, n=14) and fitness (LLE-F, n=7). On average, LLE exercised 5d/wk for 7h/wk over the past 52±1y. Each subject performed a maximal cycle test to assess VO2max and had a vastus lateralis muscle biopsy to examine capillarization and metabolic enzymes (citrate synthase, β-HAD, and glycogen phosphorylase). VO2max had a hierarchical pattern (YE>LLE>OH, P<0.05) for females (44±2>26±2>18±1 ml•kg-1•min-1) and males (53±3>34±1>22±1 ml•kg-1•min-1), and was greater (P<0.05) in LLE-P (38±1 ml•kg-1•min-1) than LLE-F (27±2 ml•kg-1•min-1). LLE males, regardless of intensity, and females had similar capillarization and aerobic enzyme activity (citrate synthase and β-HAD) as YE, which were 20-90% greater (P<0.05) than OH. In summary, these data show a substantial VO2max benefit with LLE that tracked similarly between the sexes, with further enhancement in performance trained males. For skeletal muscle, 50+ years of aerobic exercise fully preserved capillarization and aerobic enzymes, regardless of intensity. These data suggest that skeletal muscle metabolic fitness may be easier to maintain with lifelong aerobic exercise than more central aspects of the cardiovascular system.
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