I don't know that potassium specifically is a problem for me, but I am finding that I feel better if I'm careful to get enough electrolytes... mainly through salting my food and using electrolyte drinks (Nuun tablets), which have a balance of sodium, potassium and magnesium.  I'm certainly not an expert on nutrition, but my understanding is that the electrolytes work in tandem... you can't just increase one without affecting the others.  Your body will fight to regain a "normal" balance.  Ring any bells?  I've also tried "salt tablets" (which have the same mix of electrolytes), but they seem to make me a bit nauseated.

Heather