title: Physical and psychosocial factors associated with physical activity in patients with chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  To assess physical activity and sitting time in patients with chronic obstructive pulmonary disease (COPD) and to investigate which physical and psychosocial factors are associated with physical activity and sitting time.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Patients were recruited at outpatient clinics of general hospitals and from general practitioners.
  
  
  METHODS
  Patients (N=113) with mild to very severe COPD.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Physical activity and sitting time were measured with a triaxial accelerometer (24h/d).
  
  
  RESULTS
  Mean locomotion time per 24 hours was 6.8% (range, 0.7%-20.4%). Elevated physical activity was independently associated with higher self-efficacy, higher functional exercise capacity, and lower lung hyperinflation. Decreased physical activity was strongest in more severe stages of COPD, in which the patients were mainly limited by physical disease-specific factors (higher lung hyperinflation, worse dyspnea severity, worse leg muscle function, and oxygen use). In less severe patients, physical activity was independently associated with more generic factors (higher self-efficacy and the spring/summer season). Sitting time did not differ between severity stages, and longer sitting time in the total group was independently associated with more positive perception of treatment control, less autonomous motivation to exercise, not using sleep medication, and oxygen use.
  
  
  CONCLUSIONS
  Both physical and psychosocial factors were associated with physical activity in patients with COPD. The factors associated with physical activity differed between disease severity stages, raising the question of whether physical activity enhancement programs should differ as well. Sitting time should be investigated further.
authors.affiliation: Department of Pulmonary Diseases, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands.
authors.forename: Jorine E
authors.initials: JE
authors.lastname: Hartman
authors.affiliation: University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands; Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: H Marike
authors.initials: HM
authors.lastname: Boezen
authors.affiliation: Department of Human Movement Sciences, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Mathieu H
authors.initials: MH
authors.lastname: de Greef
authors.affiliation: Department of Pulmonary Diseases, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands. Electronic address: n.h.t.ten.hacken@umcg.nl.
authors.forename: Nick H
authors.initials: NH
authors.lastname: Ten Hacken
mesh_terms: D061725:Accelerometry / Q000295:instrumentation; D000368:Aged; D050218:Body Fat Distribution; D003430:Cross-Sectional Studies; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006801:Humans; D008124:Locomotion / Q000502:physiology; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D009042:Motivation; D009043:Motor Activity / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D010102:Oxygen Inhalation Therapy; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000523:psychology*; D011788:Quality of Life; D012115:Residual Volume / Q000502:physiology; D020377:Self Efficacy; D012720:Severity of Illness Index
keywords: 6-minute walk distance; 6MWD; BMI; COPD; Exercise Self-Regulation Questionnaire; FEV(1); GOLD; Global Initiative for Chronic Obstructive Lung Disease; IPQ-R; Illness Perception Questionnaire-revised; LTOT; Lung; Motor activity; Pulmonary disease, chronic obstructive; RV; Rehabilitation; SRQ-E; Sedentary lifestyle; Self efficacy; body mass index; chronic obstructive pulmonary disease; forced expiratory volume in 1 second; long-term oxygen therapy; residual volume