During the progression of COPD, airflow becomes increasingly limited, leading to decreased inspiratory and expiratory capacities and reduced elasticity of lung sacs (dynamic hyperinflation). Hyperinflation during exercise is the main cause for exertional breathlessness and poor exercise performance in COPD patients – both issues that significantly impact patients’ quality of life. Hyperinflation is also associated with an increased risk of death.

In order to increase airflow and subsequently decrease hyperinflation, research was conducted on inspiratory muscle training (IMT). IMT was tested for improving inspiratory capacity, dyspnea, exercise capacity and hyperinflation indicators in COPD patients.

Key Findings

• Progression of COPD leads to decreased respiratory capacities and reduced elasticity of lung sacs (hyperinflation).
• Hyperinflation is the main cause for dyspnea and exercise intolerance in COPD.
• Hyperinflation is associated with increased risk of death.
• 8 weeks of respiratory muscle training (RMT) reduced hyperinflation by increasing inspiratory fraction and improving exercise performance.
• RMT should therefore contribute to an increased survival rate.

Patient Impact

RMT effectively reduces hyperinflation, thereby reducing the risk of death in COPD.

Study Methods

COPD patients performed eight weeks of inspiratory muscle strength and endurance training. Maximal inspiratory pressure (PImax), inspiratory capacity and inspiratory fraction during exercise, exercise performance, breathing frequency, inspiratory flow and constant work rate were assessed during IMT and compared to a control group.

Study Results

All parameters were significantly improved due to IMT when compared to the control group.

Respiratory muscle training using IMT significantly improves respiratory function, exercise performance, inspiratory capacity and inspiratory fraction in patients with COPD. This is meaningful, as the observed increase in exercise performance and significant increase in inspiratory fraction show a significant reduction in hyperinflation due to IMT. Respiratory muscle training in COPD patients could therefore contribute to a higher survival rate as well as a marked increase in quality of life.

References

Petrovic M, et al. Effects of inspiratory muscle training on dynamic hyperinflation in patients with COPD. Int J Chron Obstruct Pulmon Dis. 2012;7:797-805.