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Comparing peak and submaximal cardiorespiratory responses during field walking tests with incremental cycle ergometry in COPD
Author(s) -
HILL KYLIE,
DOLMAGE THOMAS E.,
WOON LYNDA,
COUTTS DEBBIE,
GOLDSTEIN ROGER,
BROOKS DINA
Publication year - 2012
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/j.1440-1843.2011.02089.x
Subject(s) - cardiorespiratory fitness , medicine , heart rate , copd , physical therapy , cycle ergometer , respiratory minute volume , oxygen saturation , incremental exercise , ventilation (architecture) , vo2 max , respiratory rate , respiratory exchange ratio , tidal volume , cardiology , respiratory system , blood pressure , oxygen , mechanical engineering , chemistry , organic chemistry , engineering
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 (FEV 1 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 K4b 2 ) which included measures of heart rate and arterial oxygen saturation (SpO 2 ). Results: Between tests, no difference was observed in the peak rate of oxygen uptake ( F 3,69 = 1.2; P = 0.31), end‐test heart rate ( F 2,50 = 0.6; P = 0.58) or tidal volume ( F 3,69 = 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; F 3,62 = 4.8; P = 0.006), minute ventilation (48 ± 17 L/min; F 3,69 = 10.2; P < 0.001) and a higher end‐test SpO 2 (95 ± 4%; F 3,63 = 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.