Abstract
Determinants of change in physical activity and outcomes of physical activity promotion are unclear. In this secondary analysis of a randomised controlled trial of a physical activity intervention, we assess predictors of change in physical activity and the effects of increasing physical activity on chronic obstructive pulmonary disease (COPD) measures.
Physical activity was promoted in 94 subjects with COPD using the Omron HJ-720ITC pedometer alone or the pedometer plus a website that provides goal setting, feedback, motivational and educational messages, and social support for 3 months. We assessed forced expiratory volume in 1 s (FEV1), 6-min walk test (6MWT) distance, depression, social support and markers of systemic inflammation (C-reactive protein (CRP) and interleukin (IL)-6). Data from both groups were combined and subjects categorised as responders (increased steps per day) or nonresponders (decreased steps per day). Linear regression models explored predictors of change in physical activity and assessed the effect of response on changes in COPD measures.
The cohort of responders (n=62) and nonresponders (n=32) had mean FEV1 1.89±0.64 L (63±22% predicted). Baseline steps per day, diagnosis of depression, social support, oxygen use and season significantly predicted change in daily step count. Responders had increases in physical activity (2038 steps per day), FEV1 (308 mL) and 6MWT distance (43.6 m), and decreases in CRP (7.84 mg·L−1) and IL-6 (2.73 ng·mL−1) compared with nonresponders (p<0.0001–0.009).
History of depression, social support, oxygen use and season predict change in physical activity, and should be routinely assessed in exercise counselling. Increases in physical activity are associated with improvements in lung function, exercise capacity and systemic inflammation.
Abstract
History of depression, social support, oxygen use and season predict change in physical activity in COPD. Response to physical activity promotion is associated with improvements in lung function, exercise capacity and systemic inflammation. http://ow.ly/oOMA30kPGCE
Footnotes
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Author contributions: M.L. Moy and C.R. Richardson were involved in the conception and design of all stages of the study. A. Kantorowski, D. Homsy and R. Kadri were involved in study data collection. A. Kantorowski and E.S. Wan conducted study analyses. All authors read and approved the final manuscript. M.L. Moy and A. Kantorowski had full access to all the data in the study, and take responsibility for the integrity of the data and the accuracy of the data analysis. The views expressed in this article do not communicate an official position of the Dept of Veterans Affairs.
Conflict of interest: M.L. Moy reports personal fees (honorarium for consultancy) from AstraZeneca, outside the submitted work. She has also received a grant from the Dept of Veterans Affairs.
Support statement: This study was funded by the Dept of Veterans Affairs, Rehabilitation Research and Development Service (Career Development Award F6847W (M.L. Moy), Merit Award O1150 (M.L. Moy) and Career Development Award 2 IK2 RX002165 (E.S. Wan)). Funding information for this article has been deposited with the Crossref Funder Registry.
- Received April 13, 2018.
- Accepted July 5, 2018.
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