[Measurement of physical activity in patients with chronic obstructive pulmonary disease].

Physical activity is an important parameter related to morbidity and mortality in cardiovascular disease, metabolic syndrome/diabetes, mental disorders, cancer, and chronic obstructive pulmonary disease (COPD). In COPD, lower levels of physical activity as reported by the patients are associated with a faster annual lung function decline, increased number of hospitalizations, and higher risk of mortality. Self-reported physical activity, however, correlates only poorly with objectively quantified physical activity in patients with COPD. Recent data show that physical activity can reliably be measured in a substantial number of patients with COPD. Extrapulmonary effects of COPD are associated with reduced physical activity. Clinical characteristics commonly used to assess disease severity like the forced expiratory volume in 1 s or the 6-min walk distance only incompletely reflect the physical activity of patients with COPD.