Blood lactate concentrations during incremental work before and after maximum exercise.

Five male subjects performed three successive incremental work tests on an electronically braked cycle ergometer. The first and second tests were separated by thirty minutes of rest, the second and third by three minutes of maximum work. During the third test, venous blood lactate concentrations were still decreasing at work rates where they were increasing during the first two tests. The work rate at which rapid increases in lactate concentrations occurred during the final test coincided with the work rate where rapid increases occurred in the two initial tests. It was concluded that this point represented a threshold where a balance existed between removal and release of lactate from and into the plasma compartment, and did not coincide with the anaerobic threshold. It is postulated that steady state work at levels above this threshold would result in a continuous increase in venous lactate concentration.