Electrolytes are charged particles found in body fluids that form when salts dissolve in water or fluids. Electrolytes transmit electrical impulses necessary for proper nerve, muscle and heart function. Any imbalance in one or more of the major electrolytes could contribute to leg cramps and other complications.
The primary electrolytes found within the body are sodium, potassium, calcium and magnesium. Electrolytes are ingested through foods and fluids and are eliminated primarily by the kidneys. It is the kidneys' job to control electrolyte balance, therefore kidney failure is the most common cause of electrolyte imbalance. In addition to kidney failure, a disruption of electrolytes can occur from excessive sweating, vomiting or diarrhea and blood loss or infections.
Sodium and Potassium
Sodium is the major electrolyte found outside the cells in the extracellular fluid. Sodium plays a major role in fluid regulation and transmitting nerve impulses. Water follows salt in the body, so a gain or loss in sodium results in a gain or loss of water. If you have low sodium, called hyponatremia, you will have deficient sodium and water in excess of the sodium. This causes swelling of the cells which leads to muscle and leg cramping. Potassium is another major electrolyte that affects the excitability of nerve and muscle cells. Too much potassium causes increased activity of the cells and too little potassium causes decreased activity. Generally, the low levels of potassium result in muscle weakness, which could be associated with muscle cramping.
Calcium and Magnesium
Calcium and magnesium are both stored in the bones. Calcium also affects the excitability of nerve and muscle cells. Low levels of calcium, called hypocalcemia, causes increased muscle irritability. This can result in muscle cramping and the feeling of pins and needles in the extremities. Magnesium's functions overlap with those of potassium and calcium. Low magnesium again results in muscle irritability, causing muscle spasms and hyperactive reflexes.
Leg and muscle cramping can occur with a shift of any one of the major electrolytes. Cramping is most often associated with decreased levels of the electrolytes. Leg cramps may be early symptoms of electrolyte disturbances.
Treatment for leg cramps is focused around replacing the necessary electrolytes. In mild cases of leg cramps, simply increasing foods rich in sodium, potassium, calcium or magnesium may fix the problem. Some sports drinks contain essential electrolytes and may aid in eliminating the symptoms. In more severe cases, electrolyte supplements may be necessary.
- ModernMedicine: Restoring Electrolyte Imbalance
- Fluids and Electrolytes DeMystified; Joyce Johnson