Definition

Low potassium (hypokalemia) refers to a lower than normal potassium level in your bloodstream. Potassium helps carry electrical signals to cells in your body. It is critical to the proper functioning of nerve and muscles cells, particularly heart muscle cells.

Normally, your blood potassium level is 3.6 to 5.2 millimoles per liter (mmol/L). A very low potassium level (less than 2.5 mmol/L) can be life-threatening and requires urgent medical attention.