Several recent papers on the Conconi procedure tested on an ergometric bicycle have shown that the deflection of the heart rate is rarely seen if the procedure follows the usual protocol where the work duration remains the same at each work level. According to the di Prampero formula, work can be expressed as the energy cost of running (C), multiplied with covered distance. Therefore it is important, as in the current 400 m-track Conconi test, to keep work and not time constant at each work level. Consequently we examined heart rate and lactate profile in four groups of athletes, in following an experimental design respecting this condition. In all ergometric test runs, we observed the sought after heart rate deflection with the following lactate values: Physical education students (female) heart rate 169 with 4.6 mmol/l lactate Physical education students (male) heart rate 169 with 5.03 mmol/l lactate Amateur cyclists heart rate 178 with 2.44 mmol/l lactate Professional cyclists heart rate 171 with 1.98 mmol/l lactate.