Intermittent exercise test in chronic obstructive pulmonary disease patients: how do the pulmonary hemodynamics adapt?

PURPOSE: Endurance training is an important component of rehabilitation in patients with chronic obstructive pulmonary disease (COPD). In our study, we investigated the pulmonary hemodynamics' adaptation during a high-intensity intermittent exercise in such patients.

METHODS

Eight patients underwent a 30-min exercise, alternating a 4-min work set at their first ventilatory threshold with a 1-min exercise set at 90% of their maximal tolerated power output. Pulmonary arterial pressure was measured by means of a right heart catheter. Cardiac output was calculated using the Fick's principle applied to oxygen.

RESULTS

VO(2), cardiac output, and ventilation increased during the first minutes of exercise and remained stable thereafter. Heart rate increased significantly and progressively to its maximal value from rest to the end of the test (P < 0.001). After an initial increase, stroke volume decreased significantly (P < 0.05). Pulmonary arterial pressure increased from rest (mean +/- SEM 23.9 +/- 2.1 mm Hg) to the fifth minute of exercise (41.6 +/- 2.8 mm Hg), and decreased significantly thereafter (35.2 +/- 3.3 mm Hg at the 30th minute) (P < 0.001). Total pulmonary vascular resistance decreased from rest to the end of the test (P < 0.001).

CONCLUSION

The high-intensity 1-min bouts of work of our intermittent work exercise are well tolerated without pushing the pulmonary arterial pressure dramatically high in COPD patients.