Physiological "Side-Effects" of Lactic Acid

Lactic acid is well known as the end product of anaerobic glycolysis and thus in relation to energy metabolism. However. the produced lactate or the lactic acid exert additional effects. The oxygen transport is influenced as muscle blood flow is increased and the oxygen affinity is lowered by lactic acid. Since lactic acid accumulates in the intracellular space at the beginning of exercise and during exercise of high intensity, an osmotic gradient develops causing a water shift from the extra-cellular space into the muscle cells. This is part of the exercise-induced hemoconcentration. The acidosis in the blood caused by the released lactic acid stabilizes the volume of the red cells and is said to increase ventilation. However, the latter is controversial. That holds true for the stabilisation of the excitability of the sarkolemma by lactic acid, which was described early in this millennium.