Abstract des Autors

The purpose of this study was to compare the pattern of change in blood lactate with that of the ventilatory parameter 'excess CO2' (ExCO2 = VCO2-(Rrest VO2)) and to identify if a parallel (tracking) effect is present between the two variables during exercise. Eight trained male cyclists (mean age = 24.8 yrs., hgt = 178.3 cm., wgt = 72.0 kg.) performed a 22.1 W/min progressive intensity cycling test to compare the patterns of change in the two parameters over time. This procedure involved excess CO2 being monitored on-line at 15 sec. intervals and blood lactate concentration by approximately 52.8 sec. (corresponding to a 19.4 W intensity). Results indicated a strong relationship exists between excess CO2 and blood lactate (r=0.92, SEE=1.08). Furthermore, the blood lactate and excess CO2 curves are parallel over the region from 10 to 100% relative time. The equation developed to estimate blood lactate from excess CO2 in this region is: Blood lactate (mmoles/l = excess CO2(ml/kg/min)(0.314)-0.586. These findings suggest excess CO2 could be used as a predictor of blood lactate above 10% relative time during a progressive intensity cycling test. Verf.-Referat