Cardiac adaptations to non-linear aerobic training in patients with COPD

Abstract

While the cardiac adaptations to exercise training are well documented in healthy individuals, the effects of exercise training on cardiac function in patients with COPD are not well known. The aim of this study was to investigate the effects of aerobic exercise training on the cardiac responses to exercise in patients with COPD. 22 COPD patients and 20 healthy controls underwent incremental exercise testing and echocardiography at rest, 25, 50 and 75% workload maximum (Wmax). Subjects then performed non-linear aerobic exercise training 3x/wk for 8 weeks. Individual slope analysis of heart rate (HR) vs. cardiac output (Q) were used to estimate changes in maximal Q. Patients with COPD and controls increased VO2peak following exercise training (p 0.05). In controls, no significant cardiac adaptations were observed at rest, 25 and 50%Wmax. However, at 75%Wmax, EDV was significantly increased following training, while there were no changes in SV, ESV or maximal Q (8.27±3.32 vs. 9.49±3.28 L, p>0.05). While exercise training increased VO2peak in COPD patients, the primary cardiac adaptation appears to be reduced submaximal HR with little change in LV filling, ejection or maximal Q. This finding is somewhat in contrast to healthy individuals who also have reduced HR but this is accompanied by increased filling post training.