London, June 14 (IANS): Physical activity decreases substantially over time in patients with chronic obstructive pulmonary disease (COPD), a progressive disease that makes it hard to breathe, at all levels of severity, a new research has found.

This decline in physical activity is accompanied by a worsening of lung function and health status, and sustained physical inactivity is associated with progression of both exercise intolerance and muscle depletion, the study noted.

"Physical inactivity is associated with morbidity and mortality in COPD," said lead author Benjamin Waschki from the Pulmonary Research Institute at LungenClinic in Grosshansdorf, Germany.

"In our prospective cohort study, we evaluated the longitudinal association between changes in physical activity and disease progression in 137 patients with COPD and 26 patients with chronic bronchitis," Waschki noted.

The findings were published online in the American Journal of Respiratory and Critical Care Medicine.

Independent of the severity of COPD at baseline, steps per day, total daily energy expenditure, and daily physical activity level (PAL) decreased.

This decline in PAL was significantly associated with an increase in airflow obstruction.

"Treatment guidelines call for regular physical activity for COPD patients at all levels of severity, and our study clearly supports this recommendation," Waschki said.

"Regular exercise will improve their health and quality of life," Waschki noted.