Alterations of ionized Mg2+ in human blood after exercise

The present results shown that at the end of the ergometer test, ionized Mg2+ in both blood and serum and total serum Mg decreased. In contrast, intracellular concentration of ionized Mg increased in both thrombocytes and erythrocytes. Total intracellular Mg was unchanged making a Mg2+ shift between the intra- and extracellular compartment unlikely. The present study therefore demonstrated opposite changes of the ratio [ionized Mg2+]/[total Mg] in the intracellular and the extracellular compartment after anaerobic exercise. In in vitro experiments, similar changes of ionized Mg2+ in both compartments could be mimicked by application of weak acids like propionic and lactic acid. It is concluded changes in the fraction of ionized Mg2+ should be high enough to influence intracellular signalling and metabolic processes.