Potassium's main functions in the body are regulating BP and to a much lesser extent heart rate, so it looks like it's doing its job.

Talant is not a pre requisite to get an MD sheepskin, find a doc thats more on the ball.

An overdose of potassium, while not possible with potassium rich food alone, is possible with 'abuse' of suppliments and can cause serious slowing of the heart, even stopping it. In fact potassium is the final injection given in a lethal injection, the one that stops the prisoner's heart.

Lots of magnesium in the green leafy vegetables like kale/collards, mustard greens, turnip and beet tops, chard, arugla, mesclun(mixed peppy spring greens, check the bagged salads). Lot of calcium in there too. All of them up through chard can be cooked like or in place of spinach or eaten raw, each takes a little different cooking time and has its own flavor.
Add spinach to the list, but it contains a vitamin D blocker so take it with sun, Vitamin D is nessesary for calcium absorbsion(from food) while mag. is nessesary for calcium utilization. The body makes D when sun hits skin.

Man I ramble, its hard not to with such an intwined thing as nutriants.