Magnesium is among the electrolytes that plays a part in the heart's electrical functioning. Research seems to support this conclusion, since research has shown that it may relieve atrial fibrillation.

'Heart arrhythmia is associated with magnesium deficiency,' explains Dr Sarah Myhill, a GP located in Powys. 'In the center muscle and elsewhere in your body, calcium may be the mineral that is required to help excite muscle cells and cause contractions, whereas magnesium is active in the process of getting the muscle to unwind. If you don't have enough, muscle doesn't relax because it should and also the rhythm from the heart will go awry.'

Although she admits this can be a 'hunch', she believes that sudden adult death syndrome, when healthy adults drop dead during strenuous exercise like long-distance runs, might be causes by acute magnesium depletion. 'It's biologically plausible that individuals who're sweating and losing water and minerals as sweat and urine, couldn't have enough available magnesium to keep their heart beating. It requires further investigation.'

Canadian scientific study has done a meta-analysis of studies coping with the advantages of intravenous administration of magnesium within the acute management of atrial fibrillation. They discovered that effective rate control (reduction in heartbeat below 100 bpm) and/or conversion to normal sinus rhythm was achieved in 84% of patients given magnesium when compared with 53% given a placebo. They conclude that intravenous magnesium is part of an effective and safe technique for the acute management of atrial fibrillation.