title: Physical activity and its determinants in severe chronic obstructive pulmonary disease.
abstract: BACKGROUND
  Patients with chronic obstructive pulmonary disease (COPD) have a limited exercise capacity. Surprisingly, little is known about their levels of physical activity practice. We assessed the levels and determinants of physical activity practice in severe COPD patients.
  
  
  METHODS
  A cross-sectional systematic sample of 346 COPD patients was recruited during 1 yr in four tertiary hospitals of the Barcelona area of Spain. Patients answered a questionnaire, which included physical activity assessment, and performed spirometric tests and blood gases.
  
  
  RESULTS
  Seventy-eight percent of patients walked daily whereas 17% did not practice any physical activity. Median energy expenditure in physical activity was 109 kcal x d(-1) (IQR 24-239). The following factors were independently associated with a lower physical activity level in a logistic regression analysis: female sex (OR 2.92, 95% CI 1.11-7.70), older age (1.04, 1.01-1.07 per year), higher socioeconomic status (2.23, 1.24-4.02), diabetes (2.66, 1.40-5.06), lower physical and mental quality of life (0.93, 0.90-0.96 and 0.96, 0.93-0.98, respectively, per unit), and long-term oxygen therapy (2.07, 1.19-3.60). Neither FEV1, previous COPD admissions, body mass index, nor other treatments were related to physical activity practice.
  
  
  CONCLUSIONS
  In conclusion, one third of severe COPD patients in our study reported a level of physical activity lower than the equivalent to walking less than 15 min x d(-1). Apart from sociodemographic variables, comorbidity, health-related quality of life, and long-term oxygen therapy were the only factors independently associated with a low level of physical activity.
authors.affiliation: Respiratory and Environmental Health Research Unit, Municipal Institute of Medical Research (IMIM), Barcelona, Spain. jgarcia@imim.es
authors.forename: Judith
authors.initials: J
authors.lastname: Garcia-Aymerich
authors.forename: Miquel A
authors.initials: MA
authors.lastname: Félez
authors.forename: Joan
authors.initials: J
authors.lastname: Escarrabill
authors.forename: Ramon M
authors.initials: RM
authors.lastname: Marrades
authors.forename: Josep
authors.initials: J
authors.lastname: Morera
authors.forename: Roberto
authors.initials: R
authors.lastname: Elosua
authors.forename: Josep M
authors.initials: JM
authors.lastname: Antó
mesh_terms: D000367:Age Factors; D000368:Aged; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000453:epidemiology; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005260:Female; D015438:Health Behavior; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D010102:Oxygen Inhalation Therapy; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology / Q000503:physiopathology* / Q000628:therapy; D011788:Quality of Life; D012494:Sampling Studies; D012737:Sex Factors; D012959:Socioeconomic Factors; D013030:Spain / Q000453:epidemiology; D011795:Surveys and Questionnaires; D016138:Walking / Q000502:physiology / Q000706:statistics & numerical data