Recent studies suggested that low intensity magnetic fields (MF) exerted a stimulatory effect on the mitochondrial metabolic activity, when applied to the whole animals, organs, or single cells. However, the mechanisms and the ranges of MF strength for this stimulation are still unclear. Here we hypothesize that static low intensity MF can regulate mitochondrial electron transport chain activity as such enhance mitochondrial respiration. Nearly uniform low-strength magnetic fields were generated by Helmholtz coils, which were mounted into the water jacket of the measure chamber of an oxygraph.