On- and off-exercise kinetics of cardiac output in response to cycling and walking in COPD patients with GOLD Stages I–IV

Exercise-induced dynamic hyperinflation and large intrathoracic pressure swings may compromise the normal increase in cardiac output (Q) in Chronic Obstructive Pulmonary Disease (COPD). Therefore, it is anticipated that the greater the disease severity, the greater would be the impairment in cardiac output during exercise. Eighty COPD patients (20 at each GOLD Stage) and 10 healthy age-matched individuals undertook a constant-load test on a cycle-ergometer (75% WRpeak) and a 6 min walking test (6MWT). Cardiac output was measured by bioimpedance (PhysioFlow, Enduro) to determine the mean response time at the onset of exercise (MRTon) and during recovery (MRToff). Whilst cardiac output mean response time was not different between the two exercise protocols, MRT responses during cycling were slower in GOLD Stages III and IV compared to Stages I and II (MRTon: Stage I: 45 ± 2, Stage II: 65 ± 3, Stage III: 90 ± 3, Stage IV: 106 ± 3 s; MRToff: Stage I: 42 ± 2, Stage II: 68 ± 3, Stage III: 87 ± 3, Stage IV: 104 ± 3 s, respectively). In conclusion, the more advanced the disease severity the more impaired is the hemodynamic response to constant-load exercise and the 6MWT, possibly reflecting greater cardiovascular impairment and/or greater physical deconditioning.

► Abnormalities in respiratory system mechanics induce negative cardiovascular effects during exercise in patients with COPD.
► It is anticipated that the greater the severity of COPD the greater would be the impairment in central hemodynamic responses to exercise.
► Assessment of cardiac output can be performed non-invasively in patients with COPD across all GOLD Stages during exercise.
► Mean response time of cardiac output in the transition from rest to constant-load exercise is delayed in patients with severe as compared to moderate COPD, thus indicating that disease progression worsens the hemodynamic response to exercise.