Assessing Exercise Performance during Exacerbations of Chronic Obstructive Pulmonary Disease: Work Smarter, not Harder!

In this issue of Respiration , Johnson-Warrington et al. [7] report on a sub-analysis of data from a larger randomized controlled trial to explore incremental shuttle walk test (ISWT) performance near the time of hospital discharge. Their data provide interesting insight into some of these questions. From 52 eligible ISWT-naive patients, 39 (75%) patients with AECOPD were able and willing to complete repeat ISWTs despite this period of heightened symptom severity. The majority of patients performed exercise testing only a few days after hospital admission, and only 5 declined repeat testing due to severe symptoms. This information is, in its own right, valuable for the respiratory clinician as it demonstrates both the feasibility and acceptability of early mobilization in these acute patients. Of primary interest, the magnitude of test-retest change in ISWT distance was variable (approx. 50% improved and 50% did not), with repeat test performance potentially affected by a modest learning effect (mean difference 14 m) and/or insufficient recovery from the initial test. Despite this variability, however, the authors were able to predict repeat ISWT distance with remarkable accuracy (multiple regression analysis explaining 98.8% of the variance) using easily obtainable clinical data. Predicted and actual distances walked did not significantly differ and demonstrated good agreement, although the data were understandably derived from predominantly low total Hospitalizations due to acute exacerbation of chronic obstructive pulmonary disease (AECOPD) are characterized by prolonged bed rest, physical inactivity [1] and peripheral muscle wasting [2] that does not fully recover after discharge [3] . Given the risk of adverse health outcomes associated with these ‘acquired’ comorbidities (e.g. re-exacerbation, mortality) [4–6] and the role of physical activity in preventing these acute events [5, 6] , it is unsurprising to observe strong interest in tailoring exercise prescription to individual needs as early as possible – even during the period of hospitalization. The period of inpatient hospitalization does, after all, offer benefits in terms of environment, staff and resources to conduct assessments of exercise performance. Performing such testing during this time does not, however, come without challenge. Compared to the stable disease state, AECOPDs are associated with significantly worsened respiratory symptoms, enhanced airflow obstruction and systemic inflammation, and poorer exercise tolerance. These differences raise important questions that have not yet been answered regarding its appropriateness. For example, is it safe to perform (near maximal) exercise tests during an AECOPD? Can such tests be performed to satisfactory standards during the acute disease state? Should they be performed according to the same guidelines as during the stable state (e.g. are repeat tests necessary)? Published online: September 4, 2015