Comparison of the peak exercise response measured by the ramp and 1-min step cycle exercise protocols in patients with exertional dyspnea.

STUDY OBJECTIVES To compare the peak exercise response and determine the limits of agreement between the ramp and the 1-min step cycle protocols in a representative population of patients with exertional breathlessness attending a respiratory outpatient clinic. DESIGN Crossover with the test order double blinded and randomized. SETTING Outpatient exercise physiology laboratory. PATIENTS Twenty-two patients (12 men; mean [SD] age, 59 [8] years; FEV(1), 71% [21%]) with lung disease and/or exertional breathlessness. INTERVENTION Symptom-limited, maximum cycle exercise tests using a ramp and a 1-min step work rate (WR) protocols. The two protocols were assigned to subjects in a randomized manner. MEASUREMENTS AND RESULTS Oxygen uptake (O(2)), minute ventilation (E), heart rate (HR), WR, exercise time, and Borg scores were compared at symptom-limited peak exercise. The mean (SD) peak values for the ramp and the step protocols, respectively, were as follows: peak O(2), 1.51 (0.44) L/min and 1.49 (0.43) L/min; peak E, 50.8 (12.9) L/min and 49.9 (14.5) L/min; and peak HR, 133 (24) beats/min and 131 (22) beats/min (p > 0.05). There were no significant differences between breathlessness and perceived exertion at peak exercise. Peak WR (WRpeak) and exercise time were significantly higher using the ramp protocol: 110.5 (37.1) W vs 105.6 (35.6) W, and 8.2 (2.0) min vs. 7.6 (1.9) min, respectively. CONCLUSIONS The ramp protocol leads to a higher WRpeak, and this may have implications for exercise prescription. However, there were no significant differences between the two protocols for the peak physiologic responses. The choice of protocol for the measurement of maximal exercise capacity remains one of laboratory preference.