Potassium is an electrolyte that is critical to the function of nerve and muscles cells, including those in your heart. Low potassium (hypokalemia) has many causes. The most common cause of low potassium is excessive potassium loss in urine or from the gastrointestinal tract, such as happens during eating disorders.
Hypokalemia can be caused by overuse of laxatives; by eating disorders such as bulimia, which involves self-induced vomiting; and by prolonged fasting and starvation. This can cause weakness and irregular heart rhythms, fatigue, anorexia and decreased bowel motility. The normal potassium level is 3.5-5.0 mEq/L (this is a measure used to evaluate the level). Low potassium is defined as a potassium level below 3.5 mEq/L.
Increasing potassium in your diet and using potassium supplements are both forms of treatment. Sometimes, hospitalization may be required to add potassium. If you cannot move your arms and legs or you feel as though your heart has an irregular heartbeat, then call a medical provider immediately.