Abstract 17319: All-extremity Aerobic Exercise Training Does Not Improve Aortic Wave Reflection Characteristics and Wasted Left Ventricular Energy in Sedentary Older Adults
Introduction: Aging is associated with early return of reflected pressure waves from the lower body to the heart which augments central blood pressure and increases wasted left ventricular energy, left ventricular afterload and myocardial oxygen demand. Older endurance-trained athletes have improved wave reflection characteristics, but the effects of aerobic exercise training in previously sedentary older adults is unknown. We hypothesized that all-extremity high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) would improve aortic wave reflection characteristics and reduce wasted left ventricular energy in sedentary older adults.
Methods: Thirty-six sedentary older adults (age, 65±1 yrs, brachial systolic and diastolic blood pressures, 118±2 and 69±1 mmHg, mean±SE), free of overt cardiovascular disease, participated in the study. Subjects were randomized to HIIT (n=14), MICT (n=12) or non-exercise controls (CONT; n=10). Isocaloric HIIT and MICT were performed on a non-weight-bearing all-extremity ergometer, 4 days/week, for 8 weeks under supervision. HIIT consisted of 40 min at alternating intensities of 90% and 70% of peak heart rate, while MICT consisted of 47 min at 70% of peak heart rate. Aortic wave reflection characteristics including pressure wave travel time, reflected wave duration, augmentation index (AIx) and wasted left ventricular energy were measured using applanation tonometry (SphygmoCor, AtCor), at baseline and 8-week follow-up.
Results: In response to the intervention, pressure wave travel time (HIIT: 140±5 vs. 140±4 msec; MICT: 144±3 vs. 144±3 msec; CONT: 130±4 vs. 135±5 msec), reflected wave duration (HIIT: 220±5 vs. 214±4 msec; MICT: 211±6 vs. 203±9 msec; CONT: 218±5 vs. 213±5 msec; baseline vs. follow-up), AIx (HIIT: 29±3 vs. 27±2 %; MICT: 25±2 vs. 25±2 %; CONT: 30±2 vs. 29±2 %) and wasted left ventricular energy (HIIT: 4260±610 vs. 3489±481 dsc-2; MICT: 2652±306 vs. 2508±246 dsc-2; CONT: 3697±411 vs. 3418±316 dsc-2) did not change (all comparisons, P≥0.3).
Conclusions: All-extremity HIIT and MICT does not lead to improved aortic wave reflection characteristics or wasted left ventricular energy in previously sedentary older adults.
Author Disclosures: H. Kim: None. C. Hwang: None. J. Yoo: None. M. Hwang: None. E.M. Handberg: None. W.W. Nichols: None. D.D. Christou: None.
- © 2016 by American Heart Association, Inc.