Background: Breathlessness is the most common symptom limiting exercise in patients with chronic obstructive pulmonary disease (COPD). Exercise training can improve both exercise tolerance and health status in these patients, intensity of exercise being of key importance. Nevertheless, in these patients extreme breathlessness and/or peripheral muscle fatigue may prevent patients from reaching higher levels of intensity.
Study objective: This study was to determine whether inspiratory pressure support (IPS) applied during sub maximal exercise could enable individuals with severe but stable COPD to increase their exercise tolerance.
Participants: Twelve subjects with severe stable COPD (mean (SD): age = 63(8.2) years; FEV1 = 0.89(0.42) L (34)% predicted; FEV1/FVC = 0.31(0.07) only nine subjects completed the study.
Intervention: Each subject completed ten sessions of cycling at 25%-50% of their maximum power without NIVS and another ten sessions using NIVS.
Measurements and results: Dyspnea was measured using Borg scale. Subjects reached high levels of dyspnea 4.7 (1.81) during the sessions without NIVS vs low levels of dyspnea during the sessions using NIVS 1.3 (0.6). Exercise time during the sessions without NIVS and with NIVS was 19.37 (3.4) and 33.75 (9.5) min, respectively. Maximal workload during the sessions without NIVS and with NIVS was 27 (3.7) and 50 (10.5) watt, respectively.
Conclusion: We conclude that IPS delivered by nasal mask can improve exercise tolerance and dyspnea in stable severe COPD patients and hence this mode of ventilatory support may be useful in respiratory rehabilitation programs.