Effects of resistance training on respiratory function in patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis

Over the last decade, the potential use of resistance training (RT) for patients with chronic obstructive pulmonary disease (COPD) has gained increasing attention. Many COPD patients experience muscle dysfunction and reduced muscle mass, primarily as a result of chronic immobilization. These symptoms have been associated with reduced exercise tolerance and complaints of fatigue and dyspnea (even after minimal exertion). This paper presents findings from a systematic review that sought to: (1) present a meta-analysis of randomized controlled trials (RCT) investigating the effects of RT on respiratory function measures in patients with COPD and (2) investigate the existence of a dose-response relationship between intensity, duration and frequency of RT and assessed outcomes. A systematic literature search of MEDLINE electronic database (January 1980 to December 2009) produced a body of research on the effects of RT with a control group in patients with COPD. Data analysis involved a random effects meta-analysis, in order to determine weighted mean differences with 95 confidence intervals (95% CI) for each endpoint. All data were analyzed with the software package Review Manager V 4.2.10 (of the Cochrane Collaboration); 14 RCTs were included in the meta-analysis. Findings demonstrated that RT did not substantially increase forced expiratory volume in 1 s. In addition, the weighted mean difference was 2.71% of predicted (95% CI, -1.86 to 7.27; p = 0.25) or by absolute 0.08 L (95% CI, -0.03 to 0.19; p = 0.14). It appeared that maximum minute ventilation increased by 3.77 L/min (95% CI, -0.51 to 8.04; p = 0.08). Based on findings from the meta-analysis, RT produces a clinically and statistically significant effect on respiratory function (such as forced vital capacity) and is therefore recommended in the management of COPD.