Comparing peak and submaximal cardiorespiratory responses during field walking tests with incremental cycle ergometry in COPD

Authors

  • KYLIE HILL,

    1. Respiratory Medicine, West Park Healthcare Centre
    2. Department of Physical Therapy and Medicine, University of Toronto
    3. School of Physiotherapy and Curtin Health Innovation Research Institute, Curtin University, Bentley
    4. Lung Institute of Western Australia and Centre for Asthma, Allergy and Respiratory Research, University of Western Australia, Crawley, Western Australia, Australia
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  • THOMAS E. DOLMAGE,

    1. Respiratory Evaluation and Diagnostic Services, West Park Healthcare Centre, Toronto
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  • LYNDA WOON,

    1. Respiratory Medicine, West Park Healthcare Centre
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  • DEBBIE COUTTS,

    1. Department of Respiratory Medicine, Credit Valley Hospital, Mississauga, Ontario, Canada
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  • ROGER GOLDSTEIN,

    1. Respiratory Medicine, West Park Healthcare Centre
    2. Department of Physical Therapy and Medicine, University of Toronto
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  • DINA BROOKS

    Corresponding author
    1. Respiratory Medicine, West Park Healthcare Centre
    2. Department of Physical Therapy and Medicine, University of Toronto
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Dina Brooks, Department of Physical Therapy, University of Toronto, 160-500 University Ave, Toronto, Ontario, Canada M5G 1V7. Email: dina.brooks@utoronto.ca

ABSTRACT

Background and objective:  Field and laboratory-based tests are used to measure exercise capacity in people with COPD. A comparison of the cardiorespiratory responses to field tests, referenced to a laboratory test, is needed to appreciate the relative physiological demands. We sought to compare peak and submaximal cardiorespiratory responses to the 6-min walk test, incremental shuttle walk test and endurance shuttle walk test with a ramp cycle ergometer test (CET) in patients with COPD.

Methods:  Twenty-four participants (FEV1 50 ± 14%; 66.5 ± 7.7 years; 15 men) completed four sessions, separated by ≥24 h. During an individual session, participants completed either two 6-min walk tests, incremental shuttle walk tests, endurance shuttle walk tests using standardized protocols, or a single CET, wearing a portable gas analysis unit (Cosmed K4b2) which included measures of heart rate and arterial oxygen saturation (SpO2).

Results:  Between tests, no difference was observed in the peak rate of oxygen uptake (F3,69 = 1.2; P = 0.31), end-test heart rate (F2,50 = 0.6; P = 0.58) or tidal volume (F3,69 = 1.5; P = 0.21). Compared with all walking tests, the CET elicited a higher peak rate of carbon dioxide output (1173 ± 350 mL/min; F3,62 = 4.8; P = 0.006), minute ventilation (48 ± 17 L/min; F3,69 = 10.2; P < 0.001) and a higher end-test SpO2 (95 ± 4%; F3,63 = 24.9; P < 0.001).

Conclusions:  In patients with moderate COPD, field walking tests elicited a similar peak rate of oxygen uptake and heart rate as a CET, demonstrating that both self- and externally paced walking tests progress to high intensities.

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