Hemodynamic effects of high intensity interval training in COPD patients exhibiting exercise-induced dynamic hyperinflation

•Interval exercise training improves cardiac output at peak levels of exercise in COPD.•Interval exercise training reduces the magnitude of dynamic hyperinflation in COPD.•Mitigation of dynamic hyperinflation improves central hemodynamic responses to a given power output in hyperinflated COPD.•Rehabilitative exercise training induces a more efficient hemodynamic response to a given power output in patients with COPD.•Non-invasive measurement of cardiac output in patients with COPD may improve the evaluation of the efficacy of pharmacological and non-pharmacological interventions.

Dynamic hyperinflation (DH) has a significant adverse effect on cardiovascular function during exercise in COPD patients. COPD patients with (n = 25) and without (n = 11) exercise-induced DH undertook an incremental (IET) and a constant-load exercise test (CLET) sustained at 75% peak work (WRpeak) prior to and following an interval cycling exercise training regime (set at 100% WRpeak with 30-s work/30-s rest intervals) lasting for 12 weeks. Cardiac output (Q) was assessed by cardio-bio-impedance (PhysioFlow, enduro, PF-O7) to determine Q mean response time (QMRT) at onset (QMRTON) and offset (QMRTOFF) of CLET. Post-rehabilitation only those patients exhibiting exercise-induced DH demonstrated significant reductions in QMRTON (from 82.2 ± 4.3 to 61.7 ± 4.2 s) and QMRTOFF (from 80.5 ± 3.8 to 57.2 ± 4.9 s). These post-rehabilitation adaptations were associated with improvements in inspiratory capacity, thereby suggesting that mitigation of the degree of exercise-induced DH improves central hemodynamic responses in COPD patients.