Skeletal muscle abnormalities in patients with COPD: contribution to exercise intolerance. Med. Sci. Sports Exerc., Vol. 30, No. 7, pp. 1019-1027, 1998. Exercise intolerance in COPD patients appears to be in part because of skeletal muscle dysfunction. Studies using biopsy techniques and magnetic resonance spectroscopy have demonstrated changes in enzyme activities and metabolism that indicate reduced oxidative capacity in the peripheral muscles of these patients. Regarding the respiratory muscles, the biochemical characteristics have been studied in only a few works and the results seem to depend on the specific muscle group studied. Several factors, such as hypoxemia, nutritional status, pharmacological treatment, and deconditioning, may be responsible for these skeletal muscle abnormalities. This brief review describes the changes in peripheral and respiratory muscles in COPD patients based on data from the literature. The causes of these muscle abnormalities, their contribution to exercise intolerance, and the effects of training are then discussed. We conclude with suggested directions for future investigation using contemporary noninvasive technologies.
Laboratoire de Physiologie des Interactions, Service Central de Physiologie Clinique, CHU Arnaud de Villeneuve, 34295 Montpellier Cedex 5, FRANCE; and Laboratoire Sport Santé Développement, Faculté des Sciences du Sport, 34090 Montpellier, FRANCE
Submitted for publication March 1997.
Accepted for publication January 1998.
The authors thank Professor George A. Brooks and Jim Hokanson from the Department of Human Biodynamic and Integrative Biology, University of California, Berkeley, for their help in the preparation of this manuscript. We also thank the American College of Sports Medicine for inviting Doctor J. Mercier to present this topic at the annual meeting in Minneapolis.
Address for correspondence: I. Serres, Service EFR-Pr Préfaut, Hôpital Arnaud de Villeneuve, 34295 Montpellier Cedex 5, France. E-mail: email@example.com.