Short term and long term effects of pulmonary rehabilitation on physical activity in COPD

The central purpose of pulmonary rehabilitation is to reduce morbidity by improving functional capacity through exercise. It is still unknown if improvements in functional capacity are maintained in the long-term and if this leads to increased physical activity levels as measured by a free-living activity monitor. The hypothesis of this study was that pulmonary rehabilitation would lead to a sustained increase in standard outcome measures and in daily physical activity.

Methods: A prospective study of 47 subjects with COPD was performed, registered at ClinicalTrials.gov (Clinical Trial Number NCT 0112943). The primary outcome was a maintained improvement in standard outcome measures with a secondary aim of an increase in daily physical activity. A convenient sample of the cohort (n = 17) was re-evaluated at a third time point at 1 year.

Results: A seven week hospital based outpatient pulmonary rehabilitation program led to a significant reduction in total energy expenditure (p < 0.044) and breathlessness (Borg, p < 0.011) and improved exercise capacity (ISWT, p > 0.001, 6MWT, p > 0.002) PiMax (p > 0.007) and quality of life scores (SGRQ, p > 0.001, EQ5D, 0.025). However, pulmonary rehabilitation did not significantly change the average number of daily steps taken, time spent sedentary activity, METs consumed or daily physical activity. Indeed, all of the standard and freeliving values had returned towards the baseline value at 1 year.

Discussion: These findings show that while pulmonary rehabilitation increased exercise capacity this was not transmitted into increased daily physical activity. Hence, alternative methods to alter/affect behavioural change need to be addressed.