Chronic obstructive pulmonary disease: the contribution of skeletal muscle dysfunction to exercise intolerance

Abstract

Chronic obstructive pulmonary disease (COPD) is characterised by pathological changes in lung tissue and disordered respiratory mechanics. The exercise intolerance exhibited by individuals with COPD is related to a variety of factors including airflow obstruction, pulmonary hyperinflation, gas exchange abnormalities, and peripheral muscle dysfunction. This review examines the extent of skeletal muscle dysfunction in moderate-to-severe COPD, and its relationship to exercise intolerance. There are two distinct characteristics of skeletal muscle dysfunction in COPD – loss of muscle mass and dysfunction of the remaining muscle tissue. Abnormalities have been identified in the structural and functional determinants of skeletal muscle function (strength and endurance), and are also observed in the enzymatic profile and metabolic response to exercise in subjects with the disease. Understanding the nature of skeletal muscle dysfunction in COPD is critical to the interpretation of exercise performance in affected subjects. Furthermore, skeletal muscle dysfunction represents a partially reversible consequence of COPD, that may be ameliorated by specific exercise training strategies.

Keywords:

• CHRONIC OBSTRUCTIVE PULMONARY DISEASE
• EXERCISE INTOLERANCE
• FAT FREE MUSCLE MASS
• SKELETAL MUSCLE DYSFUNCTION
• VO2 KINETICS