Perceptual and physiologic responses during treadmill and cycle exercise in patients with COPD.
BACKGROUND
Although the cycle ergometer is the traditional mode for exercise testing in patients with respiratory disease, this preference over the treadmill does not consider perceptual responses. Our hypotheses were as follows: (1) the regression slope between breathlessness and oxygen consumption (Vo(2)) is greater on the treadmill than on the cycle ergometer; and (2) the regression slope between leg discomfort and Vo(2) is greater on the cycle ergometer than on the treadmill.


METHODS
Twenty patients (10 men/10 women) with COPD (mean +/- SD postbronchodilator FEV(1), 50 +/- 15% of predicted) used a continuous method to report changes in breathlessness and in leg discomfort during cycle and treadmill exercise.


RESULTS
Patients reported an earlier onset of breathlessness and leg discomfort during cycling. Peak ratings of breathlessness were higher on the treadmill, whereas peak ratings of leg discomfort were higher on the cycle ergometer. The regression slopes for breathlessness as a function of Vo(2) and of minute ventilation (Ve) were higher on the treadmill. The regression slopes between leg discomfort and Vo(2) were similar for treadmill and cycle exercise. Peak Vo(2) was significantly higher with treadmill exercise (mean Delta = 8%; p = 0.002).


CONCLUSIONS
Patients with COPD exhibit different perceptual and physiologic responses during treadmill walking and cycling. Although ratings of breathlessness are initially higher with cycling at equivalent levels of Vo(2), the changes in breathlessness as a function of physiologic stimuli (Vo(2) and Ve) are greater during treadmill exercise. Leg discomfort is the predominant symptom throughout cycling.
Murray
James A
JA
Pulmonary Medicine and Critical Care, Unity Health System, Rochester, NY.
Waterman
Laurie A
LA
Pulmonary Function and Cardiopulmonary Exercise Laboratories, Dartmouth-Hitchcock Medical Center, Lebanon, NH.
Ward
Joseph
J
Pulmonary Function and Cardiopulmonary Exercise Laboratories, Dartmouth-Hitchcock Medical Center, Lebanon, NH.
Baird
John C
JC
Psychological Applications, LLC, South Pomfret, VT.
Mahler
Donald A
DA
Section of Pulmonary and Critical Care Medicine, Dartmouth Medical School, Lebanon, NH. Electronic address: Donald.a.mahler@hitchcock.org.