Having had a mild heart attack, followed by periods of easily getting out of breath, my niece, who had studied natural medicine, recommended that I take calcium and magnesium to help to strengthen my muscles. Since the heart is a muscle, the results were very satisfactory, perhaps even sensational, as I am feeling a lot stronger than I have done for a long time.
I asked my Doctor before taking these tablets as I do have quite a few medicines to take. They are quite a large pill but are lozenge shaped so they do go down easily with a drink.