[Energetic equivalent of the production of plasma lactate during running of supramaximal intensity].

The energy equivalent of plasma lactate production (ELAp) represents the amount of energy that can be derived from the anaerobic glycolysis per kg body weight when the peak plasma lactate concentration (LAp) after exercise increases by 1 mM. ELAp has been calculated from the relationship between the oxygen deficit (Do2) and LAp in 32 subjects. LAp and oxygen uptake measurements were made during constant speed supramaximal running until exhaustion or during the course of constant-speed supramaximal runs of different duration interrupted by 8- to 10- min resting periods. The relationship between Do2 and LAp is described by a linear equation where the slope is equal to ELAp. This equation is: Do2 = 12.3 + 2.4 LAp (r = 0.958; P less than 0.001), where Do2 is expressed in ml O2/kg and LAp in mmol/litre (mM). These findings validate LAp measurements as an index of the anaerobic metabolism during supramaximal running.