Physical activity and its determinants in severe chronic obstructive pulmonary disease.

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.