Overview of Potassium's Role in the Body

Potassium is one of the body's electrolytes, which are minerals Overview of Minerals Minerals are necessary for the normal functioning of the body’s cells. The body needs relatively large quantities of Calcium Chloride Magnesium read more that carry an electric charge when dissolved in body fluids such as blood. (See also Overview of Electrolytes Overview of Electrolytes More than half of a person's body weight is water. Doctors think about water in the body as being restricted to various spaces, called fluid compartments. The three main compartments are Fluid... read more .)

Most of the body’s potassium is located inside the cells. Potassium Overview of Electrolytes More than half of a person's body weight is water. Doctors think about water in the body as being restricted to various spaces, called fluid compartments. The three main compartments are Fluid... read more is necessary for the normal functioning of cells, nerves, and muscles.

The body must maintain the potassium level in blood within a narrow range. A blood potassium level that is too high (hyperkalemia Hyperkalemia (High Level of Potassium in the Blood) In hyperkalemia, the level of potassium in blood is too high. A high potassium level has many causes, including kidney disorders, medications that affect kidney function, and consumption of... read more ) or too low (hypokalemia Hypokalemia (Low Level of Potassium in the Blood) In hypokalemia, the level of potassium in blood is too low. A low potassium level has many causes but usually results from vomiting, diarrhea, adrenal gland disorders, or use of diuretics. A... read more ) can have serious consequences, such as an abnormal heart rhythm or even stopping of the heart (cardiac arrest Cardiac Arrest and CPR Cardiac arrest is when the heart stops pumping blood and oxygen to the brain and other organs and tissues. Sometimes a person can be revived after cardiac arrest, particularly if treatment is... read more ). The body can use the large reservoir of potassium stored within cells to help maintain a constant level of potassium in blood.

The body maintains the right level of potassium by matching the amount of potassium consumed with the amount lost. Potassium is consumed in food and drinks that contain electrolytes (including potassium) and lost primarily in urine. Some potassium is also lost through the digestive tract and in sweat. Healthy kidneys can adjust the excretion of potassium to match changes in consumption.

Some medications and certain conditions affect the movement of potassium into and out of cells, which greatly influences the potassium level in blood.