Reduction of physical activity in patients with chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) decrease their physical activity. However, it is unknown at which stage of the disease the reduction occurs and whether dyspnea is a limiting factor. To compare physical activity between patients with COPD and controls of similar age and to assess its association with disease severity. We studied 112 patients with mild to very severe COPD and 55 controls. Lung function, six-minutes walking test (SMWT), and physical activity through the International Physical Activity Questionnaire (IPAQ) were measured. Compared to controls, physical activity was significantly reduced in COPD patients (1823 ± 2598 vs. 2920 ± 3040 METs min/week; p = 0.001). Patients were more frequently sedentary (38 vs. 11%), while controls were more often very active (31 vs. 19%) or moderately active (58 vs. 43%). Physical activity was reduced from Global Initiative for Obstructive Chronic Lung Disease (GOLD) stage 2 and from Modified Medical Research Council (MMRC) dyspnea grade 1. Weak relationships were observed between lung function, SMWT and physical activity. Physical activity decreases early in the course of the disease and when dyspnea is still mild, among patients with COPD.