title: Determinants of cardiorespiratory fitness in patients with chronic obstructive pulmonary disease, focusing on activities parallel to daily living.
abstract: OBJECTIVE
  The purpose of this study was to examine whether activities parallel to daily living (APDL) constitute a determinant index of cardiorespiratory fitness in patients with chronic obstructive pulmonary disease (COPD).
  
  
  METHODS
  Four functional physical fitness parameters were investigated in 38 male patients (mean age 69.8 +/- 6.7 years) with moderate to severe COPD. The parameters measured were muscular strength (grip strength), muscular endurance strength (arm curl, keeping a half-squat position) and regulation (walking around two cones). In addition, cardiorespiratory fitness was measured using a 6-min walking distance test (6MWD) and peak oxygen uptake (VO(2peak)) was measured during bicycle ergometer testing. Maximal inspiratory pressure (MIP) and maximal expiratory pressure were measured so as to quantify respiratory muscle strength.
  
  
  RESULTS
  There were significant correlations (P < 0.05) between the VO(2peak), muscular endurance, pulmonary function and respiratory muscle strength. There were also significant correlations of VO(2peak) to muscular endurance, muscular strength, muscular endurance strength and regulation. In stepwise multiple regression analysis, per cent predicted forced expiratory volume in 1 s and MIP appeared to be significant determinants of VO(2peak), showing a total variance of 56% (P < 0.05). For the 6MWD, the significant determinants were forced vital capacity, MIP and performance in the half-squat test, showing a variance of 59% (P < 0.05).
  
  
  CONCLUSIONS
  The results suggest that cardiorespiratory fitness is strongly affected by MIP, pulmonary function and muscular endurance strength, as APDL depend on lower-limb use.
authors.affiliation: Comprehensive Human Sciences, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan. nakamura@stat.taiiku.tsukuba.ac.jp
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Kiyoji
authors.initials: K
authors.lastname: Tanaka
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Shigematsu
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Homma
authors.forename: Kiyohisa
authors.initials: K
authors.lastname: Sekizawa
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D012129:Respiratory Function Tests; D012132:Respiratory Muscles / Q000503:physiopathology