Effects of yoga training in patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis

Introduction: Currently, several studies have assessed the effect of yoga training on the management of chronic obstructive pulmonary disease (COPD), but these studies involved a wide variation of sample and convey inconclusive results. Hence, the present study was performed a systematic review and meta-analysis to investigate the efficacy of yoga training in COPD patients. Methods: PubMed, EMBASE, the Cochrane Library, Google Scholar, and ClinicalTrials.gov databases were searched for relevant studies. The primary outcomes were forced expiratory volume in one second (FEV1), FEV1% predicted (% pred). Secondary outcomes included 6-min walking distance (6 MWD), arterial oxygen tension (PaO2), and arterial carbon dioxide tension (PaCO2). Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated, and heterogeneity was assessed with the I-2 test. Results: Five randomized controlled trials (RCTs) involving 233 patients fulfilled the inclusion criteria. Yoga training significantly improved FEV1 (WMD: 123.57 mL, 95% CI: 4.12-243, P=0.04), FEV1% pred (WMD: 3.90%, 95% CI: 2.27-5.54, P<0.00001), and 6 MWD (WMD: 38.84 m, 95% CI: 15.52-62.16, P=0.001). However, yoga training had no significant effects on PaO2 (WMD: 1.29 mmHg, 95% CI: -1.21-3.78, P=0.31) and PaCO2 (WMD: -0.76 mmHg, 95% CI: -2.06-0.53, P=0.25). Conclusions: The current limited evidence suggested that yoga training has a positive effect on improving lung function and exercise capacity and could be used as an adjunct pulmonary rehabilitation program in COPD patients. However, further studies are needed to substantiate our preliminary findings and to investigate the long-term effects of yoga training.