WHAT are electrolytes and how important are they for horse performance? Electrolytes are substances that, when dissolved in water, separate and form a pair of charged atoms or molecules. These charged atoms or molecules are called ions and are positively or negatively charged.

Examples of such ions that are important for physiological function include sodium (Na+), potassium (K+), calcium (Ca2+), and chloride (Cl-). When it comes to horses, these electrolytes, or ions, play a very important role where they help maintain nerve and muscle activity.

Body water contains a balanced electrolyte concentration, and maintaining this electrolyte balance is critical for a number of physiological processes. During intense physical exercise a horse experiences a change in several metabolic pathways and a large amount of fluid and electrolytes are lost through sweating.

A prolonged loss of fluid may cause a decrease in circulating blood in the body, along with an imbalance in electrolyte concentration. If serious levels of fluid loss are encountered then the horse can show clinical signs of dehydration and performance can be compromised.

The electrolytes sodium, chloride, magnesium, calcium, potassium, and phosphorus are all important for the correct passing of signals (conduction of electrical impulses) through the nervous system and muscle. This in turn is crucial for muscle contraction and muscle performance.

CHANGES IN METABOLISM

One should also consider the changes in metabolism that occurs during maximal exercise. These changes involve how glucose (a type of sugar) is broken down by the body. Under normal conditions much of the bodies energy needs are supplied by the breakdown of glucose through the use of oxygen (aerobic process).

During maximal exercise the supply of oxygen to cells is not enough to generate sufficient energy in the normal fashion. Now the body also starts to break down glucose to produce energy via an anaerobic (without oxygen) process.

This anaerobic process produces less energy than the normal aerobic process, but does produce it faster. Also, one of the by-products of this anaerobic process is lactic acid and under sustained maximal effort the lactic acid levels start to increase.

Iron is an important ion or electrolyte that can help here, as it has a key role in binding and transporting oxygen in the blood. As you might expect, low iron can result in inefficient oxygen binding and transport.

This in turn will lead to increased energy production through the anaerobic process and a consequently increase in lactic acid. Imbalance of blood electrolytes, with concomitant increase of blood lactic acid concentration, could be responsible for a noticeable decline of athletic performance.

It is important to note that giving additional electrolytes is not necessarily better in all cases, and that the key here is to help maintain a balanced electrolyte system when appropriate. In some cases, water replacement along with a well-balanced diet may be sufficient for a horse’s needs, other cases may benefit from additional electrolyte supplementation. If you are considering electrolyte supplementation then this should be carried out in consultation with your veterinary surgeon and/or nutritional advisor.