Abstract 14722: Lifelong Exercise Training Demonstrates a Dose Dependent Effect on Left Ventricular Myocardial Compliance and Distensibility
Purpose: Sedentary aging leads to a decrease in left ventricular (LV) chamber compliance and distensibility. Previously we showed that Masters′ athletes who train 6-7 sessions per week throughout their adult lives maintain youthful cardiac elasticity, and that LV chamber distensibility is related in a dose-dependent fashion to frequency of training. Whether this effect is a function of pericardial or myocardial compliance is unknown and the focus of this study.
Methods: 87 seniors (29 females), aged 68.6 ± 4.7 were recruited from: 1) the Aerobics Center Longitudinal Study, a well validated study of prospectively documented lifelong exercise training patterns in subjects for the past 25 years, 2) road-race results and 3) US Masters competitions. Subjects were placed into groups based on history of exercise training: < 2 sessions/wk (Q1, n=26); 2-3 sessions/wk (Q2, n=14); 4-5 sessions/wk (Q3, n=24); and > 5 sessions/wk plus competitions (Q4, n=23). Testing included right heart catheterization with transthoracic echo to define the myocardial pressure-volume relationships. PCWP, RAP, and LVEDV were measured at five cardiac loading conditions; baseline, lower-body negative pressure (-15 and -30 mmHg) and saline infusion (15 and 30 ml/kg). Transmural pressure was estimated from PCWP-RAP.
Results: The pressure-volume relationships of the myocardium demonstrated an almost doubling of stiffness with healthy sedentary aging compared to the fittest group (stiffness coefficient: Q1=0.041±0.020, Q2=0.042±0.016, Q3=0.042±0.036, Q4=0.025±0.017, p<0.05 for Q4 vs Q1,Q2,Q3).
Conclusions: When lifelong exercise training is performed >4 sessions/week, it is associated with an improvement in LV distensibility but only when exercise is performed with the highest frequency does it clearly preserve myocardial compliance. Thus, increasing “dose” of prolonged, sustained endurance training improves diastolic function and may help to prevent heart failure in the elderly.
- © 2010 by American Heart Association, Inc.