Ray Peat on Magnesium:

"Magnesium and potassium are mainly intracellular ions, sodium and calcium are mainly extracellular ions. When cells are excited, stressed, or de-energized, they lose magnesium and potassium, and take up sodium and calcium. The mitochondria can bind a certain amount of calcium during stress, but accumulating calcium can reach a point at which it inactivates the mitochondria, forcing cells to increase their inefficient glycolytic energy production, producing an excess of lactic acid. Abnormal calcification begins in the mitochondria. "
1. Calcium and Disease: Hypertension, organ calcification, & shock, vs. respiratory energy(2009)