What is hyponatremia?
Hyponatremia means that the sodium level in the blood is below normal. Your body needs sodium for fluid balance, blood pressure control, as well as the nerves and muscles. The normal blood sodium level is 135 to 145 milliequivalents/liter (mEq/L). Hyponatremia occurs when your blood sodium level goes below 135 mEq/L.