title: Disease Progression and Changes in Physical Activity in Patients with Chronic Obstructive Pulmonary Disease.
abstract: BACKGROUND
  Little is known about the role of physical activity in the course of chronic obstructive pulmonary disease (COPD).
  
  
  OBJECTIVE
  To assess changes in physical activity in COPD in relation to severity stages and changes in other disease components, and to evaluate the longitudinal association between sustained physical inactivity and disease progression.
  
  
  METHODS
  In this prospective cohort study, we measured physical activity (multisensory armband), airflow obstruction (FEV1), health status (St. George's Respiratory Questionnaire), exercise capacity (6-min-walk distance [6MWD]), muscle mass (fat-free mass [FFM]), and systemic inflammation (fibrinogen and high-sensitivity C-reactive protein) over a 3-year period in 137 patients with COPD and 26 with chronic bronchitis (normal spirometry).
  
  
  RESULTS
  Independent of baseline disease severity, steps per day, total daily energy expenditure, and (daily) physical activity level (PAL) decreased by 393, 76 kcal, and 0.04 per year, respectively. The decline in PAL was significantly associated with a decline in FEV1 and an increase in St. George's Respiratory Questionnaire total score. Changes in 6MWD, FFM, and inflammatory markers were not associated with changes in PAL. Independent of FEV1, sustained physical inactivity (i.e., PAL(T0andT1)  < 1.40) was related to a greater decline in 6MWD and FFM compared with that in patients with some level of activity (i.e., PAL(T0and/orT1) ≥ 1.40; difference, 17 m/yr and 0.87 kg/yr, respectively).
  
  
  CONCLUSIONS
  Over time, physical activity substantially decreases across all severity stages of COPD, and this decline is paralleled by a worsening of lung function and health status. Sustained physical inactivity is associated with a progression of exercise intolerance and muscle depletion.
authors.affiliation: 1 Pulmonary Research Institute, LungenClinic Grosshansdorf, Airway Research Center North, Member of the German Center for Lung Research, Grosshansdorf, Germany.|2 LungenClinic Grosshansdorf, Airway Research Center North, Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Waschki
authors.affiliation: 1 Pulmonary Research Institute, LungenClinic Grosshansdorf, Airway Research Center North, Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Kirsten
authors.affiliation: 3 Fraunhofer Institute for Toxicology and Experimental Medicine, BREATH, Member of the German Center for Lung Research, Hannover, Germany; and.
authors.forename: Olaf
authors.initials: O
authors.lastname: Holz
authors.affiliation: 2 LungenClinic Grosshansdorf, Airway Research Center North, Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors.forename: Kai-Christian
authors.initials: KC
authors.lastname: Mueller
authors.affiliation: 1 Pulmonary Research Institute, LungenClinic Grosshansdorf, Airway Research Center North, Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors.forename: Miriam
authors.initials: M
authors.lastname: Schaper
authors.affiliation: 1 Pulmonary Research Institute, LungenClinic Grosshansdorf, Airway Research Center North, Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors.forename: Anna-Lena
authors.initials: AL
authors.lastname: Sack
authors.affiliation: 4 Institute for Epidemiology, Social Medicine and Health System Research, Hannover Medical School, Hannover, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Meyer
authors.affiliation: 2 LungenClinic Grosshansdorf, Airway Research Center North, Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors.forename: Klaus F
authors.initials: KF
authors.lastname: Rabe
authors.affiliation: 1 Pulmonary Research Institute, LungenClinic Grosshansdorf, Airway Research Center North, Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors.forename: Helgo
authors.initials: H
authors.lastname: Magnussen
authors.affiliation: 1 Pulmonary Research Institute, LungenClinic Grosshansdorf, Airway Research Center North, Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors.forename: Henrik
authors.initials: H
authors.lastname: Watz
mesh_terms: D000704:Analysis of Variance; D029481:Bronchitis, Chronic / Q000503:physiopathology; D015331:Cohort Studies; D018450:Disease Progression; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D005541:Forced Expiratory Volume; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires
keywords: exercise; motor activity; musculoskeletal diseases; pulmonary disease; quality of life