Cardiovascular benefits from standard pulmonary rehabilitation are related to baseline exercise tolerance levels in chronic obstructive pulmonary disease.

Abstract

Heightened arterial stiffness is a marker of cardiovascular risk and is elevated in chronic obstructive pulmonary disease (COPD). Physical activity has been shown to reduce arterial stiffness, and our previous work has shown that arterial stiffness is related to physical activity and exercise tolerance in COPD. The purpose of this study was to evaluate whether baseline physical activity and exercise tolerance influence the cardiovascular benefits associated with standard COPD outpatient pulmonary rehabilitation (PR). A total of 66 patients with COPD were recruited from the G.F. MacDonald Centre for Lung Health, Edmonton, Alberta, prior to entering PR. Another 23 COPD patients not attending the PR program were recruited as time controls (TC). Arterial stiffness (carotid-radial pulse wave velocity, PWV), physical activity (steps taken over three days), and 6-min walk distance (6MWD) were assessed before and after PR, or before and after six weeks of standard care. Thirty-nine PR and 11TC completed all parts of the study. Following PR, there was no overall change in PWV. However, changes in arterial stiffness with PR were dependent on baseline exercise tolerance, with those patients with a 6MWD <350m showing a significant reduction in PWV following PR (6MWD >350m: 8.2±1.6 to 8.5±1.7 versus 6MWD <350m: 9.2±0.6 to 7.3±2.0m/s, p<0.05). The PWV response to PR was not influenced by baseline physical activity levels. COPD patients with low exercise tolerance appear to derive the greatest cardiovascular benefits from PR.