Effect of respiratory muscle training and pulmonary rehabilitation on exercise capacity in patients with interstitial lung disease: A prospective quasi-experimental study

Abstract

BACKGROUND: Interstitial lung diseases (ILDs) are associated with skeletal muscle dysfunction, worsening exercise capacity, and poor health-related quality of life. The clinical relevance of respiratory muscle training (RMT) as part of pulmonary rehabilitation (PR) in patients with ILD largely remains unknown with limited research evidence. OBJECTIVE: To evaluate the effect of PR on exercise capacity in patients with ILD and to study its relation with the severity of disease. MATERIALS AND METHODS: Twenty-five patients diagnosed as ILD (clinical, radiological, or histopathological basis as per the American Thoracic Society/European Respiratory Society criteria) and willing for PR were enrolled in this prospective observational study conducted between 2016 and 2017 after obtaining informed consent. All cases were subjected to supervised exercise training thrice weekly for 8 weeks, tailored as per their capacity, in addition to pharmacologic and supportive treatment. Outcome measures including 6-min walk test (6MWT), respiratory muscle pressure, dyspnea (Borg scale), and spirometry were evaluated at baseline and 8 weeks and 6 months following completion of the program and were recorded in a prestructured pro forma. RESULTS: The mean age of patients was 63.28 ± 10.88 years with majority being nonsmokers (88%) and females (60%). There was a significant improvement in the mean 6MWT distance (P = 0.02), inspiratory muscle pressure (P = 0.047), and dyspnea after exercise training when compared to at 8 weeks from the baseline. The change in spirometry values was nonsignificant. The improvement in outcome parameters was transient with no significant difference from the baseline to at 6 months after stopping PR. CONCLUSION: Exercise training significantly improves respiratory muscle strength and functional capacity in patients with ILD. Larger studies with multidimensional analysis are required to investigate the promising outcome of PR in such patients.