CONTINUUM OF CARDIOVASCULAR PERFORMANCE ACROSS A BROAD RANGE OF FITNESS LEVELS IN HEALTHY OLDER MEN

Background Although it has become clear that habitual exercise in olde r individuals can partially offset age-associated cardiovascular decli nes, it is not known whether the beneficial effects of exercise traini ng in older individuals depend on their prior fitness level. Methods a nd Results Ten sedentary men (S), age 60.0 +/- 1.6 years (mean +/- SEM ), who were carefully screened to exclude cardiac disease underwent ex ercise training for 24 to 32 weeks, and eight age-matched endurance-tr ained men (ET) stopped their exercise training for 12 weeks. All under went treadmill exercise and rest and maximal cycle exercise upright ga ted blood pool scans at baseline and after the lifestyle intervention. Before the intervention, the treadmill maximum rate of oxygen consump tion (Vo(2max)) was 49.9 +/- 1.9 and 32.1 +/- 1.4 mL . kg(-1). min(-1) in ET and S, respectively. During upright cycle exercise at exhaustio n, although heart rate did not differ between groups, cardiac index, s troke volume index, ejection fraction, and left ventricular contractil ity index (systolic blood pressure/end-systolic volume index) all were significantly higher, and end-systolic volume index, diastolic blood pressure, and total systemic vascular resistance all were significantl y lower in ET versus S. After the partial deconditioning of ET men, Vo (2max) fell to 42 +/- 2.2 mL . kg(-1). min(-1), and training of S incr eased Vo(2max) to 36.2 +/- 1.6 mL . kg(-1). min(-1). Training of S had effects on cardiovascular function that were similar in magnitude but directionally opposite those of detraining ET. All initial difference s in cardiovascular performance at peak work rate between S and ET wer e abolished with the intervention. Across the broad range of fitness l evels encountered before and after change in training status (Vo(2max) of 26 to 58 mL . kg(-1). min(-1)), cardiac index, stroke volume index , end-systolic volume index, ejection fraction, and the left ventricul ar contractility index were all linearly correlated with Vo(2max). Con clusions Exercise training or detraining of older men results in chang es in left ventricular performance that are qualitatively and quantita tively similar, regardless of the initial level of fitness before the intervention.