Interval versus Continuous High-Intensity Exercise in Chronic Obstructive Pulmonary Disease

A Randomized Trial

5 December 2006 | Volume 145 Issue 11 | Pages 816-825

Background: Guidelines recommend high-intensity continuous exercise to reduce peripheral muscle dysfunction in patients with chronic obstructive pulmonary disease but acknowledge that interval exercise might be an equally effective alternative that is better tolerated by patients.

Objective: To assess whether interval exercise is no less effective than high-intensity continuous exercise and whether it is tolerated better by patients with severe chronic obstructive pulmonary disease.

Design: Randomized, noninferiority trial.

Setting: Publicly funded rehabilitation hospital in Switzerland.

Patients: 98 patients with severe chronic obstructive pulmonary disease, with or without recent exacerbations.

Intervention: 12 to 15 supervised interval or high-intensity continuous exercise sessions (over 3 weeks) followed by exercise at home.

Measurements: Health-related quality of life determined by using the Chronic Respiratory Questionnaire (CRQ) (scores from 1 [most severe impairment] to 7 [no impairment]) after 5 weeks and number of unintended breaks during supervised exercise.

Results: Both groups experienced large improvements in health-related quality of life (increase of CRQ total scores of 1.00 [SD, 0.98] for the interval exercise group and 1.02 [SD, 1.05] for the continuous exercise group). Adjusted between-group differences between the interval exercise group and the continuous exercise group (–0.05 [95% CI, –0.42 to –0.32] for CRQ and 1.1 meters [CI, –25.4 to 27.6 meters] for 6-minute walking distance) were within the a priori defined boundaries of noninferiority (0.5 for CRQ and 45 meters for 6-minute walking distance). Twenty-one (47.9%) patients using interval exercise and 11 (24.0%) patients using continuous exercise were able to adhere to the protocol (difference, 23.9 percentage points [CI, 5.0 to 42.8 percentage points]; P = 0.014). The median number of unintended breaks lasting 1 minute or more was 2 (interquartile range, 0 to 16) for patients in the interval exercise group and 11 (interquartile range, 2 to 26) for patients in the continuous exercise group (P = 0.023).

Limitations: The study focused on initiation of exercise and not on outpatient or home-based maintenance of exercise.

Conclusions: Clinicians and patients can choose either of the 2 exercise plans to initiate physical exercise.

International Standard Randomized Controlled Trial number: SRCTN11611768.

Editors' Notes Context Exercise training improves quality of life in patients with chronic obstructive pulmonary disease, but many of these patients cannot tolerate continuous exercise. The effects of intermittent exercise are not known. Contribution The authors randomly assigned 100 inpatients with chronic obstructive pulmonary disease in a 3-week respiratory rehabilitation program to receive either high-intensity continuous exercise or high-intensity exercise alternating with low-intensity exercise (interval exercise). After 5 weeks, the 2 groups had similar respiratory symptoms in daily activities and 6-minute walking distance, but the interval exercise group adhered better to the exercise protocol. Cautions The study focused on initiation of exercise and not on outpatient or home-based maintenance of exercise. Implications For pulmonary rehabilitation, interval exercise is as effective as continuous high-intensity exercise and is better tolerated. —The Editors

 

Author and Article Information

From University of Zurich, Zurich, Switzerland; Klinik Barmelweid, Barmelweid, Switzerland; McMaster University, Hamilton, Ontario, Canada; University at Buffalo, Buffalo, New York; Italian National Cancer Institute Regina Elena, Rome, Italy; and University of Basel, Basel, Switzerland.

Acknowledgments: The authors thank the physiotherapists and physicians who participated in the study. They also thank Professor Patrick Bossuyt, PhD, University of Amsterdam, the Netherlands, for his valuable comments.

Grant Support: By AstraZeneca Switzerland (unrestricted grant), Boehringer Ingelheim Switzerland (unrestricted grant), and Klinik Barmelweid.

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Milo A. Puhan, MD, PhD, Horten Centre, University Hospital of Zurich, Postfach Nord, CH-8091 Zurich, Switzerland; e-mail, milo.puhan{at}usz.ch.

Current Author Addresses: Dr. Puhan: Horten Centre, University Hospital of Zurich, Postfach Nord, CH-8091 Zurich, Switzerland.

Mr. Büsching, Ms. vanOort, and Dr. Frey: Klinik Barmelweid, CH-5017 Barmelweid, Switzerland.

Dr. Schünemann: Department of Epidemiology, Regina Elena Cancer Institute, Via Elio Chianesi 53, 00144 Roma, Italia.

Dr. Zaugg: Kantonsspital Basel, Department of Research, ZLF 319, Hebelstrasse 20, CH-4031 Basel, Switzerland.

Author Contributions: Conception and design: M.A. Puhan, G. Büsching, H.J. Schünemann, E. vanOort, M. Frey.

Analysis and interpretation of the data: M.A. Puhan, H.J. Schünemann, M. Frey.

Drafting of the article: M.A. Puhan, H.J. Schünemann.

Critical revision of the article for important intellectual content: G. Büsching, H.J. Schünemann, E. vanOort, C. Zaugg, M. Frey.

Final approval of the article: M.A. Puhan, G. Büsching, H.J. Schünemann, E. vanOort, M. Frey.

Provision of study materials or patients: G. Büsching, E. vanOort, M. Frey.

Statistical expertise: M.A. Puhan, H.J. Schünemann, C. Zaugg.

Obtaining of funding: M.A. Puhan, M. Frey.

Administrative, technical, or logistic support: M.A. Puhan, G. Büsching, E. vanOort, M. Frey.

Collection and assembly of data: G. Büsching, E. vanOort, M. Frey.