Daily physical activity in patients with chronic obstructive pulmonary disease: a systematic review

Patients with chronic obstructive pulmonary disease (COPD) are often limited in their daily physical activity. However, the level, type and intensity of daily physical activity are not known, nor there is a clear insight in the contributing factors. The aim of this review is to describe daily physical activity of COPD patients, and to examine its relationship with demographic factors, pulmonary function, physical fitness, systemic inflammation and quality of life. A systematic literature search was conducted, including studies assessing daily physical activity in all stages of COPD by various different types of measurement techniques. In total, 47 studies were selected; 17 performance-, 20 questionnaire-, and 12 interview-based. Two studies used both a performance- and questionnaire-based method. Overall, COPD patients have a lower level and intensity of daily physical activity compared to healthy controls. This was reported by performance- as well as questionnaire-based studies, yet with a large variation (42-86% and 28-97%, respectively). Reduced daily physical activity is associated with higher levels of airway obstruction, higher levels of systemic inflammation, and lower levels of physical fitness. The association between daily physical activity and quality of life is less clear. In conclusion, this is the first review that examined the level, type and determinants of daily physical activity in COPD. It demonstrates that reduced daily physical activity frequently occurs in COPD patients, yet with a large variation. Methods of measuring and reporting daily physical activity should be more standardized.