This review aimed at examining the physiological mechanisms possibly responsible for the increase of muscle-plasmatic lactate. The increment of lactate concentration in the blood is known to be related to the increase of glycolytic activity. However, there is a possibility of rise in the lactate concentration even in predominantly aerobic conditions, pathological conditions like chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), among others, and in extreme environmental conditions, like acute exposure to great altitudes. Some studies conducted in the 60's and 70's related plasmatic lactate increase to respiratory alterations during intense physical activity, and developed the non-invasive method of determining the anaerobic threshold, called ventilatory threshold. Other reports in the 70's and 80's correlated the increase and accumulation of plasmatic lactate, with fixed blood concentrations (2 Mm and 4 Mm) or from different values of lactate. The procedure to determine the anaerobic threshold from fixed values is invasive called lactate threshold. Since then, the discussion was to find out which of the methods presents greater reliability, reproducibility, applicability and economy. This review also considered which of them would be metabolically responsible for the increase of the blood and muscle concentrations of lactate, lactate kinetics in different concentrations of oxygen and intensity of physical effort.
Lactate; Anaerobic threshold; Intense physical activity; Accumulation of lactate; Aerobic metabolism and anaerobic metabolism