Potassium is an extremely valuable electrolyte essential to heart and kidney function as well as to the maintenance of blood and urine pH.  It is the chief electrolyte in the fluid of cells.  In fact, only a small part of the total body potassium is contained in the serum.  Serum potassium values range from 3.5 to 5.0 mmol/L while the concentration inside the red blood cell is at least l5 to 20 times this amount.  While only a part of the total body potassium is found in the serum, proper serum values are critical to normal physiology, especially adrenal, heart and renal functions.  Potassium should always be viewed in relation to the other electrolytes.

Optimum Values: 4.0 to 4.7 mmol/L.

Serum potassium is increased in:

• Renal Dysfunction.
• Adrenal Cortex under function.  With hypoadrenia, you may get dizzy when you sit or stand quickly, fatigue (especially feeling tired in the morning), crave salt or salty foods, have a low systolic blood pressure, experience food and/or environmental sensitivities, feel weak or tired after colds, stress or exercise, sweat easily with exertion, get shortness of breath after very minimal exertion even though you are in shape, get colds and upper respiratory tract infections easily, etc.  Aldosterone is produced by the adrenal cortex, with insufficient production, the body loses sodium in the urine in exchange for potassium. This is why you may see a relatively low sodium with a relative elevated serum potassium with adrenal cortex underactivity. The adrenal corticosteroids also favor the anabolic over catabolic balance.  With less effect, there is less potassium in the cell and more in the serum.
• Catabolic/Dysaerobic State.  See aerobic metabolism webpage for more about this.
• Metabolic Acidosis.  The level in the serum goes up while the level inside the cell goes down as the potassium is pumped out of the cell in exchange for the excess hydrogen ion (acid).
• Respiratory Dysfunction causes elevated serum potassium because of the effect it has on making the blood and tissues more acidic due to lack of oxygen (hypoxia).
• Bradycardia.
• Massive Tissue Destruction.  Although potassium is increased in the serum, potassium may be needed because the largest store of potassium is inside the cell.  As they tissue is destroyed the potassium is lost and the blood and then excreted.
• Diabetes without adequate insulin.

Serum potassium is decreased in:

• Diarrhea and/or vomiting.
• Adrenal Cortex over function.  Aldosterone is produced by the adrenal cortex, with excess production, the body reclaims sodium from the urine in exchange for excreting potassium.  This is why you may see relatively high sodium with relative decreased serum potassium with adrenal cortex over activity.
• Several Types of Anemia.
• Metabolic Alkalosis.  Just the reverse of acidosis, the potassium level in the serum goes down while the level inside the cell goes up as the potassium is pumped into the cell in exchange for the hydrogen ion (acid).
• Diuretic Use.
• Familial Periodic Paralysis.
• Diets High in Refined Foods due to lack of potassium in the diet.
• Hypertension.
• Insulin use.  Potassium moves into cells when there is use of glucose or build-up of protein.
• Anabolic/Anaerobic States.

Taking potassium when your serum level is low without understanding the dynamics of potassium can be dangerous.  Since the serum only holds about 2% of the body's potassium, it is possible that there is an excess of potassium in the cell and a low level in the blood.  This is why it is important to know what is your aerobic status.  For example, in an anabolic/anaerobic condition, there is excess intra-cellular potassium and usually relatively decreased serum potassium.  Choosing agents like calcium and magnesium that drive the potassium out of the cell is the preferred treatment strategy rather than giving more potassium…