If you’re a runner or cardio exercise buff, you’ve likely heard of the need for electrolytes. Electrolytes are ionized (electrically charged) salts in your body. They are what your cells (especially nerve, heart, and muscle) use to maintain electro-chemical connections across cell membranes and transmit electrical impulses (nerve impulses, muscle contractions) between and among cells.
Electrolyte concentrations in your blood are managed in your kidneys. And those concentrations are changing constantly as your body moves and processes waste. When you exercise heavily, you lose electrolytes in your sweat, particularly sodium and potassium.