title: Relationship between oxygen consumption kinetics and BODE Index in COPD patients.
abstract: OBJECTIVE
  Patients with chronic obstructive pulmonary disease (COPD) present with reduced exercise capacity due to impaired oxygen consumption (VO(2)), caused primarily by pulmonary dysfunction and deleterious peripheral adaptations. Assuming that COPD patients present with slower VO(2) and heart rate (HR) on-kinetics, we hypothesized that this finding is related to disease severity as measured by the BODE Index. In this context, the present study intends to evaluate the relationship between VO(2) uptake on-kinetics during high-intensity exercise and the BODE Index in patients with COPD.
  
  
  METHODS
  Twenty males with moderate-to-severe stable COPD and 13 healthy control subjects matched by age and sex were evaluated. COPD patients were screened by the BODE Index and then underwent an incremental cardiopulmonary exercise test and a constant speed treadmill session at 70% of maximal intensity for 6 minutes. The onset of the exercise (first 360 seconds) response for O(2) uptake and HR was modeled according to a monoexponential fit.
  
  
  RESULTS
  Oxygen consumption and HR on-kinetics were slower in the COPD group compared with controls. Additionally, VO(2) on-kinetic parameters revealed a strong positive correlation (r = 0.77, P < 0.05) with BODE scores and a moderate negative correlation with walking distance (r = -0.45, P < 0.05).
  
  
  CONCLUSIONS
  Our data show that moderate-to-severe COPD is related to impaired oxygen delivery and utilization during the onset of intense exercise.
authors.affiliation: Cardiopulmonary Physiotherapy Laboratory, Nucleus of Research in Physical Exercise, Federal University of São Carlos, São Carlos, SP, Brazil. audrey@ufscar.br
authors.forename: Audrey
authors.initials: A
authors.lastname: Borghi-Silva
authors.forename: Thomas
authors.initials: T
authors.lastname: Beltrame
authors.forename: Michel Silva
authors.initials: MS
authors.lastname: Reis
authors.forename: Luciana Maria Malosá
authors.initials: LM
authors.lastname: Sampaio
authors.forename: Aparecida Maria
authors.initials: AM
authors.lastname: Catai
authors.forename: Ross
authors.initials: R
authors.lastname: Arena
authors.forename: Dirceu
authors.initials: D
authors.lastname: Costa
mesh_terms: D000368:Aged; D015992:Body Mass Index; D001944:Breath Tests; D016022:Case-Control Studies; D004417:Dyspnea / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology; D005080:Exercise Test; D017079:Exercise Tolerance; D005541:Forced Expiratory Volume; D006339:Heart Rate; D006801:Humans; D007700:Kinetics; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D012720:Severity of Illness Index; D014797:Vital Capacity
keywords: BODE Index; COPD; VO2 on-kinetics; heart rate