Potassium is a mineral essential to metabolic function and the health of all organs, tissues and cells. Normal levels of blood potassium depend on age, and pregnant or lactating women require moderately higher amounts in the bloodstream. Potassium derives from many food sources, and deficiencies generally do not result from dietary inadequacies but rather from adrenal and kidney diseases. Maintaining normal blood potassium levels is vital to your well being, and elevated or decreased amounts can cause serious damage to your health.
Normal Blood Potassium and Health
Within your body, potassium carries a small electrical charge and is classified as an electrolyte. Your body relies on potassium for both electrical and cellular activity. It is required for the electrical activity of the heart, normal body growth, and building strong muscles. It helps to balance your body's levels of acid and base, and aids in protein synthesis and carbohydrate metabolism. The average adult human stores approximately 120 g of potassium in the body, 98 percent of which is found in the cells. According to the National Institutes of Health, the normal range of blood potassium is 3.7 to 5.2 milliequivalent, or mEq, per liter. Blood potassium levels are regulated primarily by the hormone aldosterone in the kidneys.
Measuring Blood Potassium
A potassium test measures the level of potassium in the bloodstream by drawing a blood sample and analyzing the potassium concentration. Blood potassium tests are regularly performed as part of an electrolyte test and to monitor kidney disease. Because potassium plays an integral role in heart function, a potassium blood test may also be performed in instances of elevated blood pressure or cardiac problems.
Below Normal Blood Potassium
A potassium deficiency can result in a condition known as hypokalemia. Blood potassium levels below 2.5 mEq per liter are considered severe and can produce life-threatening cardiac arrhythmia. Symptoms of hypokalemia include fatigue, muscle weakness and cramps, constipation and abdominal pain. Diminished levels of blood potassium typically result from excess nutrient elimination through the urine caused by certain medications, such as laxatives, diuretics and steroids, as well as kidney disease and adrenal disorders.
Above Normal Blood Potassium
Hyperkalemia is a condition in which the blood contains higher-than-normal levels of potassium. Hyperkalemia is associated with diseases that impair the kidneys' ability to remove excess potassium from the body, and elevated amounts are released into the bloodstream. Certain medications, such as potassium-sparing diuretics and angiotensin converting enzyme, ACE, inhibitors, can reduce the body's ability to eliminate excess potassium. Symptoms of hyperkalemia include muscular weakness, tingling in the hands and feet and temporary paralysis.
Caution
Your body is highly sensitive to changes to normal blood potassium levels, and even a minor reduction in blood potassium can incur severe health consequences, such as high blood pressure and increased salt sensitivity. If you are currently taking laxatives, diuretics or steroids, have your potassium levels regularly measured by your doctor. Because of its low toxicity, the Institute of Medicine has no established upper limit for daily potassium intake. However, if you are currently taking a prescription medication or have been diagnosed with a kidney or adrenal disorder, consult your doctor before adding a supplement to your daily nutritional regimen.
