I'm 60 a -year old female who has suffered from severe leg and foot cramps at night as well as constipation for years. I recently started taking an OTC Magnesium Oxide supplement, 400 mg per day and it has helped me with those two issues (I don't have to take Miralax anymore). But I read recently that you should not take Magnesium supplements if you have a slow heartrate which I have. I've exercised my entire life (and continue to do so), so my resting heartrate is 54 bpm. Is it safe to continue taking the supplements? I would hate to give them up as they'ved helped me so much. Would it be better if I took one pill every other day? Thank you.