COPD patients often suffer from inspiratory as well as expiratory muscle weakness, and this contributes to dyspnea, reduced exercise tolerance and capacity, and reduced quality of life. Both inspiratory muscle training (IMT) and expiratory muscle training (EMT) have been shown to be beneficial for patients with reduced respiratory muscle strength and COPD. These methods have never been compared directly, however, and therefore their benefits over the other have never been directly determined.

In today’s blog, we’re looking at a study that tests both IMT and EMT together. Specific IMT and EMT were tested for their improvement of respiratory muscle strength, dyspnea and exercise capacity in COPD patients, both alone or in combination.

Key Findings

• COPD patients suffer from inspiratory and expiratory muscle weakness, contributing to dyspnea, reduced exercise capacity and quality of life.
• This study compares the effects of inspiratory muscle training (IMT) and expiratory muscle training (EMT), alone and in combination, in COPD patients.
• 12 weeks of IMT or IMT/EMT improved inspiratory muscle strength and endurance, exercise capacity and dyspnea.
• 12 weeks of EMT or IMT/EMT improved expiratory muscle strength and endurance, and exercise capacity.
• There was no additive effect of IMT plus EMT.

Patient Impact

Only a combination of inspiratory and expiratory muscle training effectively improves strength and endurance of all respiratory muscles.

Study Methods

COPD patients underwent three months of specific IMT (SIMT), specific EMT (SEMT), or SIMT+SEMT done in sequence (30 min of each SIMT and SEMT per day), at 60% of PImax and PEmax, respectively. The collected data were compared to a control group with low intensity SIMT.

Study Results

SIMT and SIMT+SEMT improved inspiratory muscle strength (PImax), inspiratory muscle endurance (PImpeak), exercise tolerance (tested via six-minute walk test) and dyspnea. SEMT and SIMT+SEMT improved expiratory muscle strength (PEmax), expiratory muscle endurance (PEmpeak) and exercise capacity. There were no differences between the groups.

SIMT and SEMT improve inspiratory and expiratory muscle strength and endurance, as well as exercise capacity. SIMT further improves dyspnea. A combination of SIMT and SEMT improves inspiratory and expiratory muscle strength and endurance, exercise capacity and dyspnea. There is no additional effect of adding EMT to IMT on inspiratory muscle strength, exercise endurance and dyspnea. Only the combination of IMT with EMT improves muscle strength of all respiratory muscles.

References

Weiner P, et al. Comparison of Specific Expiratory, Inspiratory, and Combined Muscle Training Programs in COPD. Chest. 2003;124(3):1357-1364.