Merck Manual

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Overview of Potassium's Role in the Body

By

James L. Lewis III

, MD, Brookwood Baptist Health and Saint Vincent’s Ascension Health, Birmingham

Reviewed/Revised Sep 2021 | Modified Sep 2022
VIEW PROFESSIONAL VERSION

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, drugs that affect kidney function, and consumption of too much... 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). The body can use the large reservoir of potassium stored within cells to help maintain a constant level of potassium in blood.

Did You Know...

  • Potassium was originally called kalium. So disorders involving potassium often have"kal" in their names.

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

NOTE: This is the Consumer Version. DOCTORS: VIEW PROFESSIONAL VERSION
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