The science behind electrolytes

True electrolytes must have an ionic charge.

Electrolytes are charged minerals (ions) that are balanced with a positively charged mineral (such as sodium, magnesium and potassium) and a negatively charged mineral complex (such as chloride, sulphate and carbonate), in such a way that they will dissolve and split in water making the liquid electrically conductive. Some minerals that are commonly known as electrolytes can also be found in non-electrolyte form, an example being magnesium chelate, but which will not function as an electrolyte - in order to function as such they need to be attached to a negatively charged mineral complex, such as chloride as in the electrolyte, magnesium chloride.

An overview of some important electrolytes and their functions:

  • Magnesium: The most expensive electrolyte is essential for all energy conversion, muscle function, nerve conduction, more than 300 different enzyme reactions, bone and tooth formation, and pH balance. Magnesium is essential for ATP energy, insulin production and insulin uptake. It's also essential to the optimum working at a cellular level of the Sodium:Potassium pump. Physical and emotional stress depletes magnesium from the body.
  • Potassium: Should be the most abundant electrolyte inside the cells and is essential for muscle function, nerve conduction, water balance, pH balance.
  • Sodium: The least expensive of all electrolytes and most common one found in the modern diet. Sodium is essential for thirst response, heat tolerance, muscle contraction, nerve conduction, water balance, and pH balance.
  • Chloride: The most abundant negatively charged electrolyte in the body is essential for oxygen exchange, digestion, water balance, and pH balance.

Why are electrolytes so important for sporting performance?

Every time muscles move, electrical impulses facilitate these functions. Each time your heart beats, electrical impulses make it happen. Every nerve impulse is dependent on a tiny electrical charge. Electrolytes are essential for all of these essential functions.

If electrolyte levels are low or out of balance, one of the results can be that muscles can go into cramps or spasms. The charge that electrolytes carry is also essential to regulate fluid balance (hydration) and pH balance.

Athletes have a high need for electrolytes so deficiencies of electrolytes are more common. "The competitive athlete is predestined to evolve a magnesium deficiency due to increased sweat and urine excretion. During strenuous activity magnesium is required by the organs (including muscle) and a situation is created whereby there is an increased difficulty to supply magnesium to the athletes by natural sources in sufficient amounts. Consequently continuous magnesium supplementation to the athlete must be considered as a supportive and beneficial measure during periods of long physical stress." Golf S. Magnesium and physical exercise. Journal of Trace Elements and Electrolytes, 2008; 25(4): 231.

How does homeostasis relate to electrolyte replacement?

Electrolytes, in general, and electrolyte in particular balance are so crucial to health that the body works very hard to maintain fluid levels of electrolytes within narrow ranges. This is part of the process called homeostasis.

If the body is deficient in an electrolyte, efforts will be made to absorb more from the digestive system in addition to other attempts to retain that electrolyte. As any athlete knows, when he/she becomes electrolyte deficient sweat looses its salty flavour. If there is an excess of a particular electrolyte, the body will excrete more through sweat or urine.

The typical European diet is high in sodium and as a consequence our perspiration is high in sodium, yet very low in potassium and magnesium. For this reason, clinical studies measuring the electrolytes lost through sweat are not necessarily the best guide for what to consume and replace. The body maintains stores of critical electrolytes to be used as needed. Calcium is stored in the bones, and magnesium is stored in the muscles. For those with a high need for electrolytes, it is possible to bank stores in the body by consuming electrolytes on a daily basis.