At one point after the first week of July I went for a massage as I have monthly for a few years now. For the first time, my muscles were so tense that even that would not loosen them up. They suggested a deficiency of potassium or magnesium might be the cause, but I already take magnesium, & have never been deficient in potassium. Just to be sure, I bought some potassium & took it then went for a nap. I woke up right when it kicked in & felt 10 times better by then; problem identified & corrected.