Electrolytes are substances that conduct electricity. Sodium, potassium, and chloride are the principal electrolytes in the body.

Sodium is involved in the conduction of electrical impulses through the nervous system. It's also vital for muscle function, regulation of blood and body fluids, heart activity, and metabolic functions. Potassium regulates fluid balance, nerve transmission, and contraction of the muscles. Lack of potassium upsets the electrolyte balance in the body and can cause irregular heart rhythms and even sudden death.

Dietary chloride is necessary for proper digestion of fluid and fluid balance. A lack of chloride can result in severe muscle cramps. Replacement of the electrolytes lost during sweating may be necessary during and after prolonged exercise.