SKELETAL-MUSCLE ABNORMALITIES IN PATIENTS WITH COPD - CONTRIBUTION TOEXERCISE INTOLERANCE

SERRES, I, M. HAYOT, C. PREFAUT, and J. MERCIER Skeletal muscle abnorm alities in patients with COPD: contribution to exercise intolerance. M ed Sci. Sports Exerc., Vol. 30, No. 7, pp. 1019-1027, 1998. Exercise i ntolerance in COPD patients appears to be in part because of skeletal muscle dysfunction. Studies using biopsy techniques and magnetic reson ance spectroscopy have demonstrated changes in enzyme activities and m etabolism that indicate reduced oxidative capacity in the peripheral m uscles of these patients. Regarding the respiratory muscles, the bioch emical characteristics have been studied in only a few works and the r esults seem to depend on the specific muscle group studied. Several fa ctors, such as hypoxemia, nutritional status, pharmacological treatmen t, and deconditioning, may be responsible for these skeletal muscle ab normalities. This brief review describes the changes in peripheral and respiratory muscles in COPD patients based on data from the literatur e. The causes of these muscle abnormalities, their contribution to exe rcise intolerance, and the effects of training are then discussed. We conclude with suggested directions for future investigation using cont emporary noninvasive technologies.