Electrolytes in daily life – when, how much and in what form to replenish them

Sodium, potassium, magnesium and calcium – what exactly distinguishes ‘electrolytes’ from ordinary minerals, and when does it make sense to supplement them? Find out how to recognise situations where your needs are increased and which forms of supplementation work best.

Electrolytes are a group of minerals which, in aqueous solutions, dissociate into electrically charged ions – and it is precisely this ability that enables them to perform key functions in the body. The most important electrolytes from the perspective of daily hydration are sodium, potassium, magnesium, chloride and calcium. Magnesium contributes to electrolyte balance, normal muscle function and the reduction of tiredness. Potassium contributes to normal muscle function and the maintenance of normal blood pressure. Each of these elements has health claims approved by the European Food Safety Authority, which clearly describe their role in water and electrolyte balance. The question, therefore, is not ‘are electrolytes important?’ – but ‘when does replenishing them require specific attention?’.

What exactly are electrolytes and what role do they play?

In the human body, electrolytes are present in specific concentrations in intracellular and extracellular fluids. Sodium predominates outside the cells, whilst potassium is found inside – and it is precisely this difference in concentration between these compartments that enables the conduction of nerve impulses and muscle contractions. Magnesium is involved in hundreds of enzymatic reactions, including muscle function and the proper functioning of the nervous system. Calcium plays a part in the transmission of signals between nerve and muscle cells.

In a healthy person on a balanced diet, daily electrolyte balance is usually maintained automatically. Problems only arise in situations where electrolyte loss (mainly through sweat, urine or as a result of illness) increases significantly – or when dietary intake is substantially reduced.

When the demand for electrolytes increases significantly

Heat and high temperatures – in a temperate climate, the average person loses around 0.5–1 litre of sweat per day. In hot weather and high humidity, losses can reach several litres – along with significant amounts of sodium, potassium and magnesium.

Intense and prolonged physical exertion – running, cycling, team sports, training sessions lasting over an hour. Sweat contains electrolytes (mainly sodium), which need to be replenished if the exertion is prolonged or repeated.

Saunas and intense exercise in a hot environment – regular sauna sessions are associated with significant electrolyte losses, particularly in people who combine sauna use with physical activity.

Gastrointestinal disorders with diarrhoea or vomiting – these are situations in which electrolyte replacement is crucial for health. In the event of acute diarrhoea, consult a doctor – specialised oral preparations may be recommended.

Elimination and low-carbohydrate diets – the ketogenic diet, fasting, calorie restriction. Water and sodium balance changes, and there is often an increased requirement for sodium and potassium in particular.

Sodium, potassium, magnesium – how to replenish them in practice

Sodium is the most important electrolyte lost through sweat. There is usually no shortage of it in the daily diet (table salt), but in situations involving heavy sweating, it is worth consciously increasing your intake – for example, by adding extra salt to a pre-workout meal or drinking an isotonic drink.

Potassium is found in vegetables, fruit (bananas, oranges, avocados), pulses and potatoes. Potassium supplementation in the form of citrate is well tolerated by the body and makes sense during periods of increased demand. Potassium citrate is easily absorbed and does not upset the stomach.

Magnesium is an element for which deficiencies are relatively common – the modern diet does not always provide an adequate supply. The most easily absorbed forms are magnesium citrate, bisglycinate and taurate. You can find more details in the article which magnesium is best and in the guide on magnesium citrate.

[products:potassium-citrate-380-mg-120-capsules, potassium-citrate-380-mg-60-capsules, isotonic-drink-250-g, isotonic-sport-drink-660-g]

Isotonic drinks – when are they a good choice

An isotonic drink is a beverage with an osmotic concentration similar to that of blood plasma (approximately 280–330 mOsm/l), containing electrolytes and usually carbohydrates. Its main advantage is the rate of absorption – thanks to the appropriate concentration of sugars and sodium, an isotonic drink is absorbed more quickly than plain water, whilst simultaneously replenishing electrolytes and energy.

An isotonic drink is particularly effective during and after prolonged physical exertion, in hot weather, and in situations where plain water could cause the electrolytes in the blood to become diluted (when large volumes of fluid are consumed). You can find out more about its composition and uses in the article isotonic drinks – natural hydration and in the guide

You can find the full range of electrolytes and recovery drinks in the Sport and Recovery category, and essential minerals in the Minerals category.

[Warning: People with kidney disease, heart failure or those taking diuretic medication should consult a doctor before taking potassium supplements. Excess potassium can be dangerous for people with impaired kidney function.]

Summary: Electrolytes are a group of minerals – primarily sodium, potassium and magnesium – responsible for proper hydration, nerve conduction and muscle function. Consciously replenishing them makes sense in situations of increased demand: hot weather, intense exercise, sauna sessions, a ketogenic diet or an illness accompanied by diarrhoea. In everyday practice, potassium citrate works well as a highly bioavailable form, as do isotonic drinks during and after exercise. Magnesium should be supplemented in the highly bioavailable forms of citrate or bisglycinate.