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Electrolytes - what are they and what functions do they perform?

Electrolytes are involved in many important processes in the human body.

They play a role in the conduction of nerve impulses, muscle function, maintaining hydration and regulating the body's pH level. So, in order for the body to function as it should, it is essential that the body is supplied with sufficient electrolytes on a daily basis.

Let's take a look at electrolytes, their functions, the risks of electrolyte imbalance and possible sources of obtaining them.
"Electrolyte" is a general term for particles that carry a positive or negative electrical charge. In nutrition, this term refers to essential minerals found in blood, sweat and urine. 

When these minerals dissolve in fluid, they form electrolytes - positive or negative ions used in metabolic processes. The electrolytes found in the body are salt ions: sodium, potassium, calcium and magnesium, in addition to the important chloride and phosphate ions. As they are positively or negatively charged, they are responsible for the body's water balance by attracting water molecules that are distributed throughout the body. At the same time, they enable the conduction of nerve impulses necessary for the functioning of the brain and the entire nervous system. They are indispensable for muscles, including the heart, as they influence their functioning (contraction and diastole).

The brain, to communicate with cells throughout the body, uses electrical signals sent by nerve cells. These signals are called nerve impulses and are generated by changes in the electrical charge of the nerve cell membrane. The changes occur as a result of the movement of sodium electrolyte across the nerve cell membrane. This process starts a chain reaction, moving more sodium ions (and a change in charge) along the axon of the nerve cell.

Wapń elektrolitowy jest potrzebny do wywołania skurczu mięśni. W procesie kurczenia i rozkurczania włókien mięśniowych uczestniczy również magnez, odpowiadający za rozluźnienie mięśni po skurczu.

Water must be maintained in adequate, balanced quantities both inside and outside every cell found in the human body. Electrolytes, especially sodium, help maintain fluid balance through osmosis. Osmosis is the process by which water flows across the cell membrane wall from a dilute solution (more water and fewer electrolytes) towards a more concentrated solution (less water and more electrolytes). This prevents cells from bursting due to over-filling with fluid or drying out due to dehydration.

In order to remain healthy, the human body must also regulate its internal pH. pH is a measure of the acidity or alkalinity of a solution. In the body, this level is regulated by chemical buffers or weak acids and bases that help minimise changes in the internal environment. For example, the blood is regulated to maintain a pH between 7.35 and 7.45. If the pH level does not remain within these limits, the body cannot function properly. The correct balance of electrolytes is fundamental to maintaining blood pH levels.

As can be seen, electrolyte imbalance is detrimental to health and, in rare cases, can even be fatal. 

Disorders of this balance often occur due to dehydration caused by excessive heat, vomiting or diarrhoea. This is why it is important to replenish lost fluids. Mild electrolyte disturbances do not cause any symptoms and can easily be overlooked. More serious or neglected mild disorders manifest as a feeling of fatigue, rapid or irregular heartbeat, numbness and tingling in the limbs, disorientation in space, weakness and uncontrollable muscle spasms and headaches.

The best way to achieve and maintain electrolyte balance is through a healthy, balanced diet. The main sources of electrolytes in food are fruit and vegetables. In the daily diet, a common source of sodium and chloride is table salt.

Other electrolytes can be provided in the following products:

  • Sodium: Pickled foods, cheese and table salt
  • Chloride: Table salt
  • Potassium: Fruits and vegetables such as bananas, avocados and sweet potatoes
  • Magnesium: Seeds and nuts
  • Calcium: Dairy products, fortified dairy alternatives and green leafy vegetables


A balanced diet should normally provide the body with all the electrolytes necessary for normal metabolism. Nevertheless, under certain conditions, when electrolyte loss through increased sweating or illness is greater than average, supplementation with electrolyte-containing rehydration fluid may be advisable. Providing additional electrolytes is also important to avoid the effects of heat stress. People working in elevated temperatures, non-breathing uniforms or overalls are particularly vulnerable to its effects. Normally, the body manages heat on its own by releasing it through the skin and by sweating. However, this cooling system can begin to fail in some conditions, causing body temperature to rise to dangerously high levels. The key to preventing heat stress illness is to limit the amount of time spent in high temperatures. However, taking in plenty of fluids and electrolytes is also extremely important to help the body maintain an adequate temperature. In a hot environment, it is advisable to consume water and electrolyte-containing drinks instead of other beverages, especially those containing caffeine, carbonated drinks, coffee and tea, which can worsen dehydration, as can alcohol.