Inspiratory muscle training and whole-body reconditioning in chronic obstructive pulmonary disease

To examine the efficacy of targeted inspiratory muscle training (IMT), 25 patients with moderate COPD were randomly assigned to one of three groups. Eight patients received IMT along with general exercise reconditioning, GER+IMT; nine patients received general exercise reconditioning, GER; eight patients received sham breathing exercises, CONTROL. All groups used a spring-loaded inspiratory muscle trainer; however, the GER and CONTROL groups breathed through these devices at only 15% of their maximal inspiratory pressure. The GER+IMT group increased the load on these devices until at 6 wk the load was equal to 80% of their maximal inspiratory pressure. All patients exercised three times per week for a 12-wk period in supervised sessions. Analysis of covariance revealed no significant differences in spirometric measurements, maximal inspiratory pressure, or maximal oxygen consumption among any of the three groups after the intervention (p > 0.05). Twelve-minute walk distance was significantly greater in the GER+IMT and GER groups than in the CONTROL group (p = 0.03). After the intervention, there was a trend (p = 0.08) for treadmill time to be greater for the GER+IMT and GER groups than for the CONTROL group. Dyspnea ratings at different exercise intensities were not found to be significantly different among the three groups after the intervention. These results demonstrate that GER+IMT and GER alone are equally effective in improving exercise performance in patients with COPD. Additionally, the combination of GER and IMT does not appear to provide any clinically significant improvements in exercise performance or perceptions of dyspnea during exercise when compared with GER alone.