Electrolytes: What they are and what they help us with

Water is the most essential component of the human body, occupying 45-70% of total body weight. The human body contains about 60% or 45 litres of water and the water content of muscle tissue is about 70-75% while adipose tissue contains about 10-15%.

The body is unable to store water, as the kidneys eliminate any excess. On the other hand, it is possible to cause dehydration of the body due to an imbalance between water intake and water loss.

The average water loss per day for a healthy person is estimated at 500-1500 ml from the skin as evaporated water, 100 ml to litres with sweat, 400-500 ml during exhalation and finally 50-200 ml with our faeces. The intake is mainly covered by the fluids we drink, by food and by the various oxidations that take place in our body.

Why are we sweating?;

When we make an intense effort, the heart sends more blood to the periphery (muscles, brain and skin). This results in an increase in blood pressure and dilation of the blood vessels. The sweat glands are then activated, resulting in the elimination of sweat, which consists of water, sodium chloride, urea, amino acids and lactic and uric acid. We would be good to replenish the water but always within reasonable limits.

Dehydration

Under normal circumstances, we all have fluid loss in the form of sweat, tears, stool and urine. We make up for this loss by eating foods that contain fluids and by taking fluids. When the body cannot replenish the fluids it loses through vomiting, diarrhoea, fever or exercise, it is driven to dehydration.

The concentration of electrolytes in sweat is lower than the concentration in the blood. Consequently, dehydration due to sweat loss leads to an increase in blood electrolyte concentration.

What are electrolytes?;

When we talk about electrolytes, we mean Sodium, Potassium and Chlorine. Their action is extremely important because they affect both the distribution of fluids in the body (retention -distention) and the smooth functioning of the nervous system. Let's look at these three elements in detail:

• Sodium: its most familiar form is salt (sodium chloride) and is present mainly in nerve cells, covering all the properties of an electrolyte. As it is present in almost all foods, its deficiency in a healthy person is rare. It can cause rare atony and weakness of the nervous system and is observed in:

1. Exhausting work
2. Polyuria from diabetes mellitus or kidney failure

• Taking diuretics

1. After intense and long hours of exercise

Excessive intake is also a problem as it is responsible for cellulite, fluid retention and blood pressure. Salted foods and all foods that have a salty taste are rich sources of sodium. Its enemies are too much water and its competitor potassium.

• Potassium: is considered the main antagonist of sodium and has all the characteristics of an electrolyte, as well as the reduction of renal calcium excretion and, in combination with magnesium, the protective effect on nephrolithiasis. Lack of it can cause sluggishness, weakness and heart arrhythmias. Hyperkalemia is rarely observed, perhaps with potassium preparations for pathological conditions.

Sources of potassium are dried fruits, nuts, vegetables, bananas, mushrooms. Its enemy is of course sodium, intensive boiling in a lot of water and diuretic drugs.

• Chlorine: is the third electrolyte with all the elements mentioned. It plays a key role in the production of hydrochloric acid in the stomach, and is not found alone in food but only in combination with sodium. Its deficiency is rare and its enemy is too much water.

Need for electrolytes

The minimum daily requirements for sodium, chlorine and potassium are 500, 750 and 2000 mg respectively.. The daily food intake ensures their replenishment. However, in cases of severe diarrhoea and prolonged sweating, plasma electrolyte levels may be significantly reduced. In such cases, the intake of electrolytes through specially formulated hydration solutions is recommended.

Electrolytes and exercise

Research by sports scientists has shown that there is a need for electrolyte coverage of athletes especially when the sport exceeds 1 hour. There we have to feed our athlete and during the sport with special solutions, which apart from water and carbohydrates (direct absorption) are enriched with electrolytes (mainly sodium in the amount of 0.5-0.7 grams/liter). It is usually advisable for the athlete to consume them at every opportunity at intervals of about 15 minutes.

Good hydration practice after exercise involves replenishing electrolytes and fluids lost through sweat. The amount of solution to be consumed must be greater than the amount of sweat lost. This can be easily calculated based on the difference in the athlete's body weight before and after exercise.

But even if the right amount of solution is consumed, these fluids will not be retained by the body if they do not contain the right amount of electrolyte, specifically sodium. This amount should therefore correspond to the amount of sodium lost through sweat.

In cases of prolonged exercise, where the athlete chooses a drink with a low concentration of electrolytes, a simultaneous decrease in blood sodium concentration is observed, leading to hyponatremia. In sports of increased endurance, the phenomenon is often observed at the end of the race, if the solution consumed at that time does not have the necessary electrolyte composition is not retained by the body.

Electrolyte solutions

To understand the correct composition of the sports solution, we need to know their loss from sweat. The presence of sodium in the liquid to be consumed is important as it improves the taste of the solution and helps the absorption of glucose and water in the small intestine.

Especially when the duration of exercise exceeds 3-4 hours, the addition of sodium to the solution helps to avoid hyponatraemia. The ideal sodium concentration in the sports drink is between 20-40 mmol/L.

The need for potassium replenishment during exercise is not necessary because it circulates in the blood and increases naturally with exercise. After exercise, however, it is recommended to replenish with a litre of orange juice for example.

Electrolytes and children

Dehydration is a phenomenon that often occurs in children. For the moderate degree of dehydration that can be found in a child, we have the following symptoms:

• Dry mouth
• Crying without tears
• Sleepiness
• Less than 6 wet nappies a day in infants

The treatment of dehydration is done by replacing the lost fluids but at the same time the cause of dehydration must be stopped. Regarding electrolytes, we start with special electrolyte solutions, which can be found in flavors to find the child's preference. It is advisable to administer a little solution every few minutes to avoid bowel disturbance or fear of vomiting.

By Christiana Abatzi, dietician-nutritionist