RESUMO
BACKGROUND: The effect of exercise protocol on the slope of the relationship between minute ventilation and carbon dioxide production (deltaVE/deltaVCO2) has not fully been studied. METHODS: Twenty-five healthy volunteers performed two sessions of incremental bicycle exercise, one with a rapidly increasing staged (RIS: 25W every minute) protocol and another with a slowly increasing staged (SIS: 25W every 3 minutes) protocol to calculate the deltaVE/deltaVCO2. Six of the subjects also participated in sessions of steady state exercise (SSE) test various work rates. RESULTS: The deltaVE/deltaVCO2 was significantly lower when the RIS protocol was used than when the SIS protocol was used (23.3 +/- 2.3 vs. 24.9 +/- 1.8, p < 0.001). Data from the subjects who also underwent SSE sessions revealed that the deltaVE/deltaVCO2 from the SSE protocols was greater than that from the RIS protocol and identical with that from the SIS protocol (125.1 +/- 3.7. 20.6 +/- 1.7, and 24.0 +/- 2.7, respectively, p < 0.05), while arterial partial pressure of carbon dioxide during exercise was not different between the protocols (43.0 +/- 3.3. 39.9 +/- 2.1, and 40.8 +/- 2.6, respectively, n.s.). C ONCLUSIONS: Care must be taken in the interpretation of the values of deltaVE/deltaVCC2, as they are influenced by the difference in exercise protocol.
