Abstract 18540: Lifelong Exercise Training Results in a Dose Dependent, Upward Shift of the Frank-Starling Relationship in Healthy Seniors
Background: Masters' athletes, highly competitive seniors who train 6-7 sessions per week, benefit from an upward shift of the Frank-Starling relationship when compared to sedentary seniors (Circulation. 2004;110:1799-1805). However it is not clear how much training necessary to achieve this improvement in ventricular performance; defining this dose-response relationship was the focus of this study.
Methods: Subjects (age > 65; n=86, 60 M, 26 F) were recruited from the Aerobics Center Longitudinal Study, a well validated cohort which has prospectively documented lifelong exercise training patterns in subjects for 25 years and regional race results. Subjects were stratified into four groups based on their history of exercise training: ‘Group 1' <2 sessions/wk (n=27); ‘Group 2' 2-3/wk (n=15); ‘Group 3' 4-5/wk (n=24); and ‘Group 4' 6-7/wk plus regular competitions (n=20). All subjects underwent right heart catheterization, echocardiography and cardiac output (Qc) measurement (foreign gas rebreathing). PCWP, left ventricular end-diastolic volume (LVEDV) and Qc were measured at baseline, during decreased cardiac filling by lower-body negative pressure (-15 & -30 mm Hg) and after rapid saline infusion (15 & 30 mL/kg). Stroke volume index [SVI=(Qc/HR)/BSA] and preload recruitable stroke work [PRSW=(SVI*MAP)/LVEDV] were calculated.
Results: The Frank-Starling relationships by group are presented in Figure 1 (group mean ± SEM; quadratic fit) showing a greater increase in SVI for any given PCWP associated with increasing training dose. Group mean peak VO2 ± SD is also reported. Preload recruitable stroke work was similar between all groups.
Conclusion: Lifelong exercise training has a dose-dependent effect on the Frank-Starling relationship. Increasing levels of prolonged, sustained exercise training improve ventricular performance as evidenced by upward shifts in the Starling curve, resulting in increased stroke volume and greater functional capacity.
- © 2010 by American Heart Association, Inc.