Electrolytes — What Are They? What Happens If You Don't Have Enough?

Foam letters arranged to spell "electrolytes"

He awoke in a pool of sweat, with numb legs and crushing chest pain.

ER doctors ruled out heart attack and cardiovascular disease. He felt better, but the leg numbness remained. Wanting to understand what had happened, he asked the specialists what he could do to prevent another frightening episode. “Drink Pedialyte®,” they told him, “and cut back on the green tea.”

Strange advice? Here’s the explanation: His electrolytes were out of balance, so he needed to take in more of them (by drinking Pedialyte, which contains electrolytes) and stop washing them out of his body (green tea is a diuretic — a substance that causes you to urinate more frequently).

Fluids and electrolytes are both essential for our cells, organs and body systems to work properly. Electrolytes are electrically charged minerals and compounds that help your body do much of its work — producing energy and contracting your muscles, for example. Sodium, chloride, potassium and calcium are all types of electrolytes. (See chart below for more examples.) We get them from what we eat and drink. Electrolyte levels are measured in blood tests, and their levels must stay within a fairly small range, or serious problems may arise.

What Do Electrolytes Do?


  • Regulate the fluid levels in your blood plasma and your body.
  • Keep the pH (acid/alkaline) of your blood in the normal range (7.35-7.45, slightly alkaline).
  • Enable muscle contractions, including the beating of your heart.
  • Transmit nerve signals from heart, muscle and nerve cells to other cells.
  • Help blood to clot.
  • Help build new tissue.

What Can Cause an Electrolyte Imbalance?

An electrolyte imbalance can be caused by:

  • Losing fluids as a result of persistent vomiting or diarrhea, sweating or fever.
  • Not drinking or eating enough.
  • Chronic respiratory problems, such as emphysema.
  • Higher-than-normal blood pH (a condition called metabolic alkalosis).
  • Medications such as steroids, diuretics and laxatives.

To ensure that you have enough electrolytes, stay hydrated and eat foods rich in electrolytes, including spinach, turkey, potatoes, beans, avocados, oranges, soybeans (edamame), strawberries and bananas.

With the exception of sodium*, it's not likely that you'll get too many of any electrolytes from your diet. (The risk may be higher if your kidneys are not working well.) However, supplements can cause problems — for example, too much calcium can increase your risk of kidney stones — so always talk to your doctor before you start to take them.

*Processed foods and restaurant meals can be very high in sodium.

Normal Range* Notes
Sodium Na+


Older folks with chronic illness who have low sodium will have more symptoms than younger, healthy people with the same low sodium level.

Chloride Cl-


May not have symptoms unless level changes are severe. Since it is closely tied to sodium, some people have symptoms of hyponatremia (low sodium levels in the blood).

Potassium K+


Works with sodium to maintain water balance and acid/base balance. With calcium, it regulates nerve and muscle activity.

Magnesium Mg+2


Mostly in bones, with about 1% in extracellular fluid (body fluid outside the cells). Important for enzyme reactions.

Calcium Ca+2


99% in teeth and bones. Calcium in blood is ionized (carries an electrical charge) and helps regulate cell function, heart rate and blood clotting. The body needs vitamin D to absorb calcium. (Ionized calcium level range is 4.7-5.28.)

Phosphate/Phosphorus PO4-


Blood tests measure inorganic phosphate. About 85% is in bones; most of the rest is inside cells. Phosphate helps build/repair bones and teeth, stores energy, contracts muscles and enables nerve function. The body needs vitamin D to absorb phosphorus.

*Ranges may vary by lab.


Low sodium, also called hyponatremia, causes water to move into cells. High sodium, or hypernatremia, causes fluid to move out of the cells. When either of these things happens in brain cells, it can cause personality changes, headache, confusion and lethargy. If the sodium drop is severe, it can result in seizures, coma and death. A key symptom of hypernatremia is thirst.


Low chloride (hypochloremia) may be due to excessive vomiting, suctioning of stomach contents, or “loop” diuretic medications, often used to treat fluid retention caused by heart or kidney problems or high blood pressure. High chloride (hyperchloremia) often results from diarrhea or kidney disease.

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Low potassium (hypokalemia) may not cause symptoms, but it may affect how your body stores glucogen (your muscles’ source of energy) or cause abnormal heart rhythms. A level under three can cause muscle weakness, spasms, cramps, paralysis and respiratory problems. If it continues, kidney problems may occur. High potassium (hyperkalemia) may not cause any symptoms, although you may experience muscle weakness or abnormal heart rhythms. If the level goes very high, the heart can stop beating.


Low calcium (hypocalcemia) may not cause symptoms, but chronically low levels can cause changes in skin, nails and hair; yeast infections; and cataracts. As levels drop, muscle irritability and cramps (particularly in legs and back) may develop. Calcium under seven causes changes in your reflexes (hyperreflexia), muscle spasms, spasms of the larynx (voice box) and seizures. High calcium (hypercalcemia) may not cause symptoms. As calcium rises, constipation, loss of appetite, nausea, vomiting, abdominal pain, neuromuscular symptoms and bowel obstruction (ileus) may occur. Above 12, emotional swings, confusion, delirium and stupor occur. Above 18, it may result in shock, kidney failure and death. Persistent or severe hypercalcemia can damage kidneys and cause heart problems, including rhythm changes and heart attack.


Low magnesium (hypomagnesemia) may cause symptoms similar to low potassium or calcium. An extremely low level can be life-threatening. High magnesium (hypermagnesemia) may cause low blood pressure, breathing problems (slow, ineffective breathing) and heart problems (cardiac arrest).


Low phosphate (hypophosphatemia) can cause muscle weakness, respiratory failure, heart failure, seizures and coma. It may be caused by very poor nutrition, certain diuretic medications, diabetic ketoacidosis/DKA, alcoholism and severe burns. (DKA is a serious complication of diabetes in which cells burn fat instead of glucose. This creates ketones, which enter the blood and turn it acidic. Normal blood is slightly alkaline.) High phosphates (hyperphosphatemia) may not cause symptoms. It may be due to tumor lysis syndrome, overwhelming infection, chronic kidney disease, parathyroid gland disorder, or acidosis (blood pH more acidic than normal).