Physical and psychosocial factors associated with physical activity in patients with chronic obstructive pulmonary disease

Objectives: 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.

Design: Cross-sectional study.

Setting: Patients were recruited at outpatient clinics of general hospitals and from general practitioners.

Participants: Patients (N=113) with mild to very severe COPD.

Interventions: Not applicable.

Main outcome measures: 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.