Michinari Hieda, Erin Howden, Shigeki Shibata, Naoki Fujimoto, Paul S. Bhella, Jeffrey L. Hastings, Takashi Tarumi, Satyam Sarma, Rong Zhang, Benjamin D. Levine

BACKGROUND: The dynamic Starling mechanism, as assessed by beatby-beat changes in stroke volume and left ventricular end-diastolic pressure, reflects ventricular-arterial coupling. It deteriorates with age, and is preserved in highly trained masters athletes. Currently, it remains unclear how much exercise over a lifetime is necessary to preserve efficient ventricular-arterial coupling. The purpose of this study was to assess the dose-dependent relationship between lifelong exercise training and the dynamic Starling mechanism in healthy seniors.
METHODS: One hundred two seniors were recruited and stratified into 4 groups based on 25 years of exercise training history: sedentary subjects (n=27, <2 sessions/week), casual exercisers (n=25, 2–3 sessions/week), committed exercisers (n=25, 4–5 sessions/week), and competitive Masters Athletes (n=25, 6–7 sessions/week). The dynamic Starling mechanism
was estimated by transfer function gain between beat-by-beat changes in diastolic pulmonary artery pressure, a surrogate for left ventricular enddiastolic pressure, and stroke volume index.
RESULTS: The transfer function gain of pulmonary artery pressure–stroke volume index was markedly enhanced in committed and competitive exercisers compared with more sedentary seniors and correlated with higher peak oxygen uptake (Vo2) and lower left ventricular stiffness. The power spectral density of pulmonary artery pressure was greater in sedentary adults than in committed and competitive exercisers, whereas the power spectral density of stroke volume index was greater in competitive exercisers than in the other groups.
CONCLUSIONS: There is a graded, dose-dependent improvement in ventricular-arterial coupling with increasing amounts of lifelong regular exercise in healthy older individuals. Our data suggest that the optimal dose of lifelong endurance exercise to preserve ventricular-arterial coupling with age appears to be at least 4 to 5 sessions per week.

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