Potassium is an electrolyte that we all know we need, and just like sodium can be excreted through too much sweating, from vomiting/diarrhea, certain medications (like diuretics or laxatives), and not absorbed due to a poor diet.  Potassium is key in helping to regulate many of the bodies functions such as blood pressure, bone mass, the nervous system, muscle function, heart/kidney/adrenal gland functions.  One current reason why a lot of younger people become hypokalemic (low potassium levels) is due to fad diets like the ‘colon cleansing’ diets; you are taking in fluids, pills, etc that act as a diuretic,  because you are not eating a normal diet, having numerous bowel movements, and your potassium levels drop down. On the opposite side, hyperkalemia is usually due to kidney dysfunction (the inability to excrete potassium seen in renal failure and people on dialysis), with disorders of the adrenal glands, and due to certain medications like ACE inhibitors (cardiac medication), Non-Steroidal Anti Inflammatory Drugs  (i.e. ibuprofen), Angiotensin II Receptor Blockers (cardiac medication), and potassium-sparing diuretics (i.e. aldosterone).