It has become increasingly recognized that skeletal muscle dysfunction is common in
patients with chronic obstructive pulmonary disease (COPD). Muscle strength and
endurance are decreased, whereas muscle fatigability is increased. There is a reduced
proportion of type I fibers and an increase in type II fibers. Muscle atrophy occurs with a
reduction in fiber cross-sectional area. Oxidative enzyme activity is decreased, and
measurement of muscle bioenergetics during exercise reveals a reduced aerobic capacity …

Skeletal muscle dysfunction occurs in patients with chronic obstructive pulmonary disease
(COPD) and affects both ventilatory and nonventilatory muscle groups. It represents a very
important comorbidity that is associated with poor quality of life and reduced survival. It
results from a complex combination of functional, metabolic, and anatomical alterations
leading to suboptimal muscle work. Muscle atrophy, altered fiber type and metabolism, and
chest wall remodeling, in the case of the respiratory muscles, are relevant etiological …