Inspiratory muscle function in chronic obstructive pulmonary disease (COPD)

Impaired inspiratory muscle function is an important cause of disability in patients with chronic obstructive pulmonary disease (COPD). Lung hyperinflation, malnutrition, hypoxaemia, hypercapnea, and steroid treatment act synergistically to reduce inspiratory muscle strength and endurance. The current review assesses each of these factors in relation to physiological mechanism of action, normal inspiratory muscle function, and the pathophysiology of COPD. Treatment strategies, including nutritional repletion and inspiratory muscle training, are reviewed with respect to evidence of their clinical effectiveness. Although more research is needed, the evidence reviewed here would suggest that inspiratory muscle endurance training may have beneficial effects at both muscular and functional levels in COPD patients.