title: Distribution of muscle mass and maximal exercise performance in patients with COPD.
abstract: OBJECTIVE
  To investigate the distribution of reduction in lean body mass (LBM) and whether LBM in legs (LBMlegs) can be a determinant of maximal exercise performance in COPD patients.
  
  
  METHODS
  Thirty-eight male outpatients with COPD (mean +/- SD FEV1, 47.4 +/- 24.0% of predicted) who underwent complete pulmonary function testing were classified into two groups according to FEV1 expressed as a percentage of predicted value. Group A comprised 21 patients with mild-to-moderate airflow limitation (FEV(1) > or =35% predicted), and group B comprised 17 patients with severe airflow limitation (FEV1 < 35% predicted). LBM, which represents skeletal muscle mass, was measured by dual energy x-ray absorptiometry (DXA) and was assessed separately in arms, legs, and trunk. Maximal oxygen uptake VO2max was measured during maximal exercise on a cycle ergometer.
  
  
  RESULTS
  LBM in each region was expressed as a percentage of ideal body weight (IBW). LBM in arms (LBMarms)/IBW, LBMlegs/IBW, and LBM in trunk (LBMtrunk)/IBW were significantly depleted in group B compared with group A (p < 0.01). LBMlegs expressed as a percentage of total LBM (LBMlegs/total LBM) was significantly lower in group B (p < 0.05), although there was no significant difference in LBMarms/total LBM and LBMtrunk/total LBM between the two groups. VO2max correlated significantly with LBMlegs/IBW in group A, but not in group B. By stepwise regression analysis, LBMlegs/IBW appeared to be a significant predictor of VO2max in group A, while not in group B.
  
  
  CONCLUSIONS
  LBMlegs was a significant predictor of maximal exercise performance in patients with mild-to-moderate airflow limitation, but not in patients with severe airflow limitation who had disproportional reduction in LBMlegs.
authors.affiliation: Second Department of Internal Medicine, Nara Medical University, Nara, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yoshikawa
authors.forename: T
authors.initials: T
authors.lastname: Yoneda
authors.forename: H
authors.initials: H
authors.lastname: Takenaka
authors.forename: A
authors.initials: A
authors.lastname: Fukuoka
authors.forename: Y
authors.initials: Y
authors.lastname: Okamoto
authors.forename: N
authors.initials: N
authors.lastname: Narita
authors.forename: K
authors.initials: K
authors.lastname: Nezu
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D001823:Body Composition; D015444:Exercise; D005080:Exercise Test; D006801:Humans; D007866:Leg; D008173:Lung Diseases, Obstructive / Q000534:rehabilitation*; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D010809:Physical Fitness