Abstract
Purpose: One of the well-known but less-investigated effects of pulmonary rehabilitation in patients with chronic obstructive pulmonary disease (COPD) is the change in breathing pattern toward a more efficient one (higher tidal volume [VT], lower breathing frequency). Evidence suggests this change can be obtained only with supervised, high-intensity exercise training (ExTr). However, some patients either do not have such programs available or are unable to exercise at higher intensity. We evaluated the effects of a 12-wk, moderate-intensity, home-monitored ExTr program using a metronome on the breathing pattern, oxygen saturation (SpO2), and dyspnea during exercise in patients with COPD.
Methods: Twenty-one patients with COPD (7 female, aged 64-85 yr) performed spirometry, incremental, and endurance walking tests (at 60% of maximal walking speed) on a treadmill before and after training. During the endurance test, patients were equipped with an instrument that continuously monitored ventilation (
E), breathing pattern, and SpO2. Patients trained at home for 12 wk, 30 min/d for at least 4 d/wk at moderate intensity. A metronome paced the walking speed.
Results: Sixteen patients completed the program. After training, a significant change was observed in breathing pattern (lower
E and
E/VT ratio; P < .001), a higher SpO2 (P < .001), and a lower dyspnea perception at the same work intensity (P < .01). The
E/VT ratio and SpO2 during exercise were significantly related (r = 0.56, P = .001).
Conclusion: A change in breathing pattern towards more efficient ventilation can be obtained with a moderate, home-monitored ExTr program with a pace that is controlled by a metronome. Decreased
E/VT was associated with an improved SpO2 during exercise.