Abstract
BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disease associated with respiratory muscle weakness and activity-limiting symptoms such as dyspnea. Respiratory muscle strength training (RMST) is an empirically validated therapy to increase respiratory muscle strength. The theoretically-informed, technology-enhanced RESPiratory FITness (RESP-FIT) intervention for COPD is a 6-week combined inspiratory and expiratory muscle strength training program with symptom measurement in real time via ecological momentary assessment (EMA). OBJECTIVES: In addition to hypothesis-generating purposes, the purpose of this randomized control pilot study was to explore whether observed effects (on symptoms, patient-reported outcomes, and respiratory muscle strength) support carrying out a future large-scale trial of RESP-FIT. METHODS: A total of 30 adults with COPD were randomized to intervention (n=15) or control groups, with the intervention group undergoing 6 weeks of mHealth-enhanced RMST. Daily symptom data were collected in real time over the 6-week intervention period using EMA. RESULTS: Compared to the control group, participants in the intervention group reported decreased dyspnea and anxiety, increased happiness, and improved respiratory muscle strength. However, reports of fatigue and sleep disturbance increased in the intervention group compared to the control group. CONCLUSION: Results support the hypothesis that the 6-week RESP-FIT program will improve respiratory muscle strength, emotional state (anxiety and happiness), and breathlessness in COPD but may contribute to fatigue, at least in the short term. Future work is needed to determine the efficacy of RESP-FIT, determine mechanisms of action on dyspnea and fatigue, and conduct within-participant comparisons of EMA data to explore individual or environmental fluctuations in COPD symptoms.