Physical performance and muscular characteristics in different stages of COPD

Scand J Med Sci Sports. 2009 Dec;19(6):865-70. doi: 10.1111/j.1600-0838.2008.00858.x. Epub 2008 Oct 13.

Abstract

This study has examined exercise capacity and muscle morphology in patients with different severities of chronic obstructive pulmonary disease (COPD). Twenty-three patients and 12 healthy matched controls were recruited. Based on the severity of airflow obstruction, patients were divided into two subgroups. Exercise capacity was determined using a 6-min walk test. Muscle fiber composition, fiber area and number of satellite cells/muscle fiber were determined in muscle biopsies using immunohistochemistry. A progressive decline in exercise capacity was noted with ascending disease severity. Furthermore, a correlation between reduction in exercise capacity and changes in muscle fiber composition was observed in COPD. The group with severe and very severe COPD had a lower proportion of type I and a higher proportion of type IIa fibers compared with the other groups. In severe and very severe COPD, a reduction in fiber area of type IIa fibers was also seen. The number of satellite cells/muscle fiber did not differ between the groups. In conclusion, a decline in exercise capacity occurs already in mild and moderate COPD, indicating that the 6-min walk test is a reliable indicator of disease severity. Furthermore, changes in skeletal muscle morphology are associated with disease severity while muscle regenerative capacity is not altered.

MeSH terms

  • Aged
  • Body Composition
  • Exercise Test
  • Exercise Tolerance / physiology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Muscle, Skeletal / physiology*
  • Pulmonary Disease, Chronic Obstructive / physiopathology*
  • Severity of Illness Index