Physical activity in COPD

• Main Author: Raste, Yogini
• Other Authors: Hopkinson, Nicholas ; Polkey, Michael
• Published: Imperial College London 2016
• Subjects: 610
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.733096

Reduced physical activity is an important feature of Chronic Obstructive Pulmonary Disease (COPD). This thesis explores the importance of technical, environmental and patient factors in physical activity in COPD. Activity monitors are integral in accurately measuring physical activity in COPD but, to date, commercially available monitors had not been validated in this patient group. The first study (Chapter 3) was a multicentre validation study of 6 physical activity monitors in a laboratory setting in 40 COPD patients, against a gold standard of indirect calorimetry from a portable metabolic kit. Three triaxial accelerometers were found to be the most accurate activity monitors Chapter 4 describes a validation study of 4 activity monitors in a domestic setting in 20 UK-based patients. The gold standard of indirect calorimetry from the doubly labelled water method was used. Chapter 5 describes a multicentre longitudinal study of 236 COPD patients. Physical activity was measured at 3 different time points over 12 months with 2 triaxial monitors to assess the effect of time, geographic location and climatic conditions on physical activity. There was a significant effect of time with a decline in physical activity over time. There was also a significant effect of temperature and day length with lower levels of activity associated with lower temperatures and shorter day length. This has implications for future studies in COPD using physical activity as an outcome measure. A decline in physical activity over time across several European centres supports the importance of physical activity in the course of COPD and early intervention to attenuate its decline. The breathing response to the initiation of exercise in COPD and its association with daily physical activity levels was investigated (Chapter 6). A rapid shallow pattern of breathing on exertion is commonly found in COPD, which worsens with disease severity. However, the hypothesis that this breathing pattern would be associated with lower levels of daily physical activity was not proven.