potassium

Meaning of potassium: Both unusually high and unusually low blood potassium levels can disrupt the heart's electrical rhythm, making this mineral closely monitored during illness.

Definition of potassium

Potassium is a mineral and electrolyte present throughout the body, with the great majority located inside cells rather than in the surrounding fluid or bloodstream. It plays a central role in generating the electrical signals that allow nerve cells to transmit impulses and muscle cells, including heart muscle, to contract normally.

Potassium levels within the body are tightly regulated, largely through the kidneys, which adjust how much potassium is excreted in urine based on dietary intake and the body's overall needs. Potassium is obtained through diet, with foods such as fruits, vegetables, and dairy products serving as common sources.

Because potassium is so closely tied to normal heart and muscle function, both an excess and a deficiency of potassium in the blood can be dangerous, potentially disrupting the heart's normal electrical rhythm, which is why blood potassium levels are frequently measured during illness or when certain medications are used.