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Exercise Outcomes After Pulmonary Rehabilitation Depend on the Initial Mechanism of Exercise Limitation Among Non-Oxygen-Dependent COPD Patients^*

^* From the Department of Pulmonary and Critical Care Medicine, Duke University Medical Center, Durham, NC.

Correspondence to: Neil MacIntyre, MD, FCCP, Room 7453, Box 3911, Duke University Hospital, Durham NC 27710; e-mail: neil.macintyre{at}duke.edu

Study objectives: Pulmonary rehabilitation (PR) that includes exercise training can improve exercise tolerance and quality of life for patients with COPD. However, the degree of benefit from PR is variable. We hypothesized that the exercise response to PR varies depending on the initial factors that limit exercise.

Design, setting, participants, and measurements: We retrospectively analyzed the change in exercise capacity after PR in 290 nonhypoxemic patients with COPD. We classified patients into the following subgroups based on the primary limitation seen on initial exercise testing: (1) ventilatory-limited (VL); (2) cardiovascular-limited (CVL); (3) mixed ventilatory/cardiovascular-limited (VLCVL); and (4) non-cardiopulmonary-limited (NL). We compared outcomes among subgroups.

Results: In the entire study population, PR led to increased timed walk distance (30.3%; p < 0.0001) and maximal oxygen consumption (O₂max) [84.8 mL/min; p < 0.0001]. Stepwise multiple regression selected age, ventilatory reserve at peak exercise, and exercise arterial oxygen pressure as individual predictors of improvement in O₂max. O₂max increased in the VL subgroup (30.4 mL/min; p = 0.008), the CVL subgroup (109.0 mL/min; p < 0.0001), the mixed VLCVL subgroup (61.3 mL/min; p < 0.0001), and NL subgroups (110.5 L/min; p < 0.0001). The improvement in O₂max was greater in the CVL subgroup than in the VL subgroup (p < 0.0001). Timed walk distance improved to a similar degree in all subgroups (26 to 36%).

Conclusions: Patients with nonventilatory exercise limitations experience the greatest increase in O₂max after PR. However, even patients with severe ventilatory limitation can improve exercise tolerance with PR.

Key Words: exercise therapy • exercise tolerance • lung diseases • obstructive • oxygen consumption • walking

This article has been cited by other articles:

				V. S. Probst, T. Troosters, F. Pitta, M. Decramer, and R. Gosselink Cardiopulmonary stress during exercise training in patients with COPD Eur. Respir. J., June 1, 2006; 27(6): 1110 - 1118. [Abstract] [Full Text] [PDF]