Electrolytes - Part 2: The Individual Electrolytes and Electrolyte Deficiency
SodiumSodium is the most important (and most well-known) mineral for hydration because it is the primary electrolyte in blood and the one lost in the greatest amounts in sweat (and urine). Sodium literally helps hold water in the bloodstream, so blood volume decreases whenever sodium is lost. Outside of maintaining hydration, sodium serves a number of other important functions, including in the transmission of the nerve impulses that cause muscles to contract, the maintenance of proper blood pressure, the function of all cell membranes, the absorption of water and nutrients, and in assuring normal kidney function.
Chloride, like sodium, is found mostly outside of the cells of the body and is therefore referred to as an extracellular ion or electrolyte. It is the second most abundant electrolyte in sweat and blood and, as such, is absolutely critical for proper hydration and maintenance of blood volume during rest and exercise. Chloride also plays important roles in digestion, fluid absorption, nerve and muscle function, and maintaining acid-base balance.
Potassium is the most abundant mineral inside our cells; in fact, only a very small amount of potassium is found outside of the cells. Potassium is partly responsible for the fact that most of the water in our bodies is found inside cells, making potassium a very important mineral in maintaining normal hydration. However, as with all the minerals in the body, potassium plays multiple roles as it is critical to maintaining proper heart function, controlling blood pressure, regulating nerve and cell membrane activity, promoting bone health, and maintaining kidney function.
Magnesium is only lost in small amounts in sweat but is an essential mineral because it is a cofactor in over 300 different enzyme systems inside our cells. These enzyme systems regulate protein synthesis, blood pressure, bone structure and growth, nerve and muscle function, and systemic control of blood sugar. Most magnesium is found inside bones and other cells, with only a tiny amount in the bloodstream, so its intracellular presence also helps keep cells hydrated.
Calcium is also found in small amounts in sweat and, just like potassium and magnesium, is primarily found in bone and inside cells. The majority of the calcium in our body is dedicated to bone structure and function but it also plays a critical role in blood vessel function, heart function, muscle function, and hormone secretion. Furthermore, because calcium is lost in sweat and urine, it is important to replace it by consuming foods and beverages that contain the mineral.