Pulmonary Rehabilitation in COPD: Effect of 2 Aerobic Exercise Intensities on Subject-Centered Outcomes—A Randomized Controlled Trial

Abstract

BACKGROUND: Exercise training is an important component of pulmonary rehabilitation, but it remains questionable how training intensity affects patient-centered outcomes. The aim of this study was to compare the effects of 2 aerobic training intensities on health-related quality of life (HRQOL), symptom control, and exercise tolerance in subjects with COPD. METHODS: Thirtyfour subjects with mild to very severe COPD participated in an equivalence/non-inferiority randomized controlled trial with a parallel group blinded to 60 or 80% maximum work rate (W max ) aerobic training intensity. The intervention was an out-patient pulmonary rehabilitation program conducted 3 times/week for 8 weeks. Outcomes were assessed with the St George Respiratory Questionnaire (primary outcome), Mahler's dyspnea index, London Chest Activity of Daily Living scale, 6-min walk test, and constant-load and incremental exercise tests. RESULTS: Subjects were randomly allocated to aerobic training intensity of 60% W max (group 1, n ‫؍‬ 17) or 80% W max (group 2, n ‫؍‬ 17). Although there were significant improvements in all outcomes for both groups, there were no between-group differences in mean change in the St George Respiratory Questionnaire (P ‫؍‬ .31, 95% CI ؊12.0 to 3.9), Mahler's dyspnea index (P ‫؍‬ .38), London Chest Activity of Daily Living scale (P ‫؍‬ .92), 6-min walk test (P ‫؍‬ .50, 95% CI 6.2-71.1), constant-load exercise test (P ‫؍‬ .50), and incremental exercise test (P ‫؍‬ .12). There was only one exercise-related adverse event of cardiac symptoms. CONCLUSIONS: Aerobic training intensity of at least 60% W max has a positive impact on COPD patient-centered outcomes, with no additional benefit of increasing intensity to 80% W max in HRQOL, symptom control, and exercise tolerance, challenging the present clinical attitude of rehabilitation professionals. (ClinicalTrials.gov registration NCT01944072.)

Exercise training in COPD: What is it about intensity?

“…While both groups significantly improved cycle endurance time and quality of life, there were no between‐group differences, except for a significantly greater improvement in the symptom score in the home training group. In the most recent study of patients with moderate COPD (FEV 1 ≈ 55% predicted), exercise training at 80% W peak ( n = 17) was compared with 60% W peak ( n = 17) . All participants were trained, supervised, three times per week for 30 min and, according to patient preference, on either a treadmill (76% of participants) or cycle ergometer (24% of participants).…”

“…While the study by Casaburi et al . provides some evidence that a higher training intensity elicits greater physiological outcomes, the larger and more recent studies of Maltais et al and Santos et al concur with the lack of a dose–response in physiological outcomes to exercise intensity in healthy older subjects . Based on the evidence available, it is doubtful that higher training intensities improve patient‐centred outcomes, such as quality of life, any more than lower intensity training.…”

“…The range of data is limited and clustered around certain intensities. However, it is interesting to note that in the range of intensities of studies which have compared high‐ versus low‐intensity continuous exercise training (i.e. 50–90% W peak ), there is no relationship between training intensity and increase in W peak per hour of exercise training (r = 0.04, P = ns).…”

Physical therapy in chronic obstructive pulmonary disease (analysis of the evidence-based medicine)

“…All studies found that pulmonary rehabilitation programs or individual physical therapy programs were effective in improving the quality of life [12][13][14][15][16][17], physical endurance [12][13][14][15][16][18][19][20][21][22][23], respiratory muscle strength [13,18,23], reducing symptoms of CoPd [14,16,19,23], improving the function of external breathing [16,[24][25][26], blood parameters [22,27], cognitive functions [21], functional state of muscles [28], survival rates [29,30], and reducing the number of hospital days [31]. The main part of investigations was devoted to the comparison of therapeutic rehabilitation programs that included several components and referred to stable patients with CoPd.…”

Is Two Better Than One? The Impact of Doubling Training Volume in Severe COPD: A Randomized Controlled Study

“…In patients with COPD, there are studies comparing the physiological benefits of different endurance training intensities [7,8,9], within or across different exercise training modalities (continuous vs. interval training) [10,11,12]. The optimal training intensity that is tolerable by the majority of patients and that yields the greatest physiological benefits is still unclear [13].…”