Electrolytes

What are electrolytes?

Electrolytes are minerals that, once dissolved in the body's water, carry an electrical charge. This charge enables nerve conduction, muscle contraction, and the distribution of water between the inside and outside of cells. Five of these are directly relevant to athletes: sodium, potassium, chloride, magnesium, and calcium. Bicarbonate and phosphate complete the list from a strictly physiological standpoint.

Each occupies a different compartment. Sodium and chloride dominate the extracellular environment and determine the volume of water the body retains; potassium and magnesium are mainly intracellular; calcium acts at very low and finely regulated concentrations.

An electrolyte drink therefore does not "recharge" minerals in a broad sense: it primarily replaces what sweat carries away—and sweat does not carry away these five minerals in equal measure.

Why is sodium the most important electrolyte?

Because it is by far the electrolyte found in the largest quantity in sweat. Human sweat is essentially a dilute solution of sodium chloride; potassium, magnesium, and calcium are much rarer, to the point that their loss during an ordinary session remains marginal compared to daily dietary intake.

It is also the electrolyte most systematically underdosed in mass-market products. The reason is commercial: sodium has a bad reputation and gives a salty taste that is not expected from a flavored drink. Many hydration products thus provide a few tens of milligrams of sodium per dose, whereas a long session causes a much greater order of magnitude of loss.

The simple reflex to adopt is this: look for the sodium line in milligrams per prepared dose, not the "rich in electrolytes" claim on the front of the sachet. A product that lists eight minerals in symbolic doses is worth less than a product that contains three, correctly dosed.

How many electrolytes do we lose through sweating?

This is the real difficulty in this category, and the reason why no universal dosage exists: losses vary enormously from person to person. Two parameters are involved, and both are largely individual.

The first is the sweat rate, which depends on body mass, training level, heat acclimatization, and clothing. The second is the salinity of sweat, a relatively stable and hardly modifiable individual characteristic: "heavy sweaters" are identified by white traces on their clothes and the distinctly salty taste of their sweat.

Combined, these two parameters result in incomparable losses from one individual to another for the same session. Hence our mistrust of universal dosage tables: the only reliable method remains observing your own practice—weight before and after a long session, salt traces, cramps, digestive tolerance.

When is an electrolyte drink really useful, and when is water sufficient?

Let's be clear: for a one-hour gym session in a temperate room, water is sufficient, and daily food intake covers the rest. Selling an electrolyte drink in this case is like selling flavored water. Situations where it has a real benefit are identifiable:

• heat and humidity, which increase sweat rate much faster than effort intensity;
• sessions lasting more than an hour, particularly in endurance sports—running, cycling, trail running, swimming, racket sports;
• the "heavy sweater" profile, recognizable by white deposits on clothing;
• fasting sessions or low-carbohydrate diets, where a decrease in insulin is accompanied by increased renal sodium excretion;
• back-to-back sessions: two sessions in one day, training camps, weekend competitions;
• sauna and cutting phases with poorly managed sodium restriction.

Outside of these cases, a normal diet provides sodium in abundance, potassium from fruits and vegetables, magnesium from nuts and whole grains. And an electrolyte drink will not solve a caloric deficit or lack of sleep.

Osmolarity and sugar: why do a few carbohydrates accelerate absorption?

This is the technical point that separates a true sports drink from salt water. In the small intestine, sodium and glucose are absorbed together, via a common transporter: the passage of one facilitates that of the other, and water follows by osmosis. This is the principle of oral rehydration solutions.

Two practical consequences. A strictly sugar-free drink is not absorbed as efficiently as a drink containing some carbohydrates—which doesn't make it useless, but explains the composition of endurance formulas. And a too concentrated drink slows gastric emptying and causes the classic digestive discomforts of long efforts. The goal is an isotonic or slightly hypotonic solution.

This is the only area in this category where European regulations allow for specific claims, and it is worth quoting the exact wording. For carbohydrate and electrolyte solutions: "Carbohydrate-electrolyte solutions contribute to the maintenance of endurance performance during prolonged endurance exercise" and "Carbohydrate-electrolyte solutions enhance the absorption of water during physical exercise". These claims can only be used if the drink meets strict composition conditions: from 80 to 350 kcal per liter, of which at least 75% are provided by carbohydrates with a high glycemic index, from 20 to 50 mmol of sodium per liter—i.e., 460 to 1,150 mg—and an osmolality between 200 and 330 mOsm/kg of water. A sugar-free tablet does not meet these conditions and therefore cannot claim these effects; this is useful information when comparing an endurance powder to an energy drink or a pre-workout, neither of which falls into this category.

Two minerals also have their own claims, regardless of the drink: magnesium "contributes to electrolyte balance", "contributes to the reduction of tiredness and fatigue" and "contributes to normal muscle function"; potassium "contributes to normal muscle function" and "contributes to the normal functioning of the nervous system". Sodium, on the other hand, has no authorized claims. See our magnesium section if this is your area of interest.

Exertional hyponatremia: the risk no one mentions

The danger during long efforts is not only drinking too little. It is also drinking too much plain water. By diluting plasma sodium, excessive water consumption without salt intake can cause exertional hyponatremia, which manifests as headaches, nausea, confusion, hand swelling, and, in severe cases, neurological disorders. The described cases mainly concern marathons, ultras, and endurance events in hot weather, among participants who are often slow and very conscientious about hydration.

The paradox is worth understanding: the symptoms resemble those of dehydration, which leads to drinking more and worsens the situation. It is in this context that a sodium-containing drink makes the most sense. If you experience suggestive signs during or after a long event, you should stop drinking plain water and seek medical advice without delay.

Frequently Asked Questions

What are electrolytes?

Minerals that, dissolved in the body's water, separate into electrically charged particles—ions. This charge enables nerve impulse conduction, muscle contraction, and water distribution between the inside and outside of cells. Nothing specific to sport here: the term comes from chemistry and refers to any substance that conducts current when dissolved. In the human body, the five that matter are sodium, potassium, chloride, magnesium, and calcium.

What are the main electrolytes?

Sodium, potassium, chloride, magnesium, and calcium. For athletes, sodium and chloride are those that sweat carries away in truly significant quantities.

What is an electrolyte drink?

A drink whose composition is calculated to replace minerals lost through sweat and to be absorbed quickly. It is neither an energizer nor a pre-workout: it generally contains neither caffeine nor stimulants. Two families coexist. Endurance formulas combine sodium and carbohydrates—these are the only ones that can claim European health claims on performance maintenance and water absorption, under strict composition conditions. Sugar-free tablets and powders provide minerals alone: less effective for water absorption, but useful outside of exercise or on a low-carbohydrate diet.

Why drink electrolytes?

To replace what perspiration causes to be lost when losses become significant, and so that the water drunk is absorbed rather than immediately eliminated. For a short session in a temperate environment, the benefit is nil—tap water and daily food intake are more than enough.

When to take electrolytes?

During effort in long sessions or in hot weather, sipping regularly rather than all at once; before a morning event in summer; after a very sweaty session if the next meal is far off. Outside of these situations, there is no particularly indicated time: it is not a supplement to be taken daily.

Where to find electrolytes?

First in food, and that's where most people already meet their needs: table salt and salty foods for sodium and chloride, fruits, vegetables, and potatoes for potassium, nuts, whole grains, and legumes for magnesium, dairy products for calcium. Then in pharmacies, in the form of oral rehydration solutions, designed for digestive losses. And finally in sports nutrition, in powders and tablets dosed for effort: this is what we offer in this section, online and in-store in Vendargues, about ten minutes from Montpellier.

How to increase your electrolytes?

The question should be reversed: in a healthy person who eats normally, there is generally nothing to increase. Blood levels are very closely regulated by the kidneys, and additional intake is simply excreted. Situations that truly warrant increasing intake are specific: abundant and prolonged sweating, heat, low-carbohydrate or low-salt diet, digestive losses. In these cases, salt your meals normally, eat fruits and vegetables, and use a properly dosed drink during exercise. If you suspect a real imbalance—unusual fatigue, repeated cramps, palpitations—a blood test and a doctor are what's needed, not a sachet.

Which water contains electrolytes?

All mineral waters contain them, in very unequal quantities indicated on the label in milligrams per liter. Highly mineralized waters provide magnesium and calcium, but none reach the sodium levels of a sports drink.

Which drink contains electrolytes?

Sports drinks and hydration powders, oral rehydration solutions from pharmacies, and to a lesser extent, salty broths and milk. Sodas provide practically none.

How to make a homemade electrolyte drink?

Water, a pinch of table salt, a source of carbohydrates, and lemon juice for taste: it's functional and very economical. The limitations are dosage precision, taste stability, and the absence of magnesium.

Which electrolyte to choose?

One whose sodium is correctly dosed, whose label details the milligrams per prepared dose, and whose taste allows you to drink it regularly during exercise. These three criteria, in this order, are more valuable than the number of advertised minerals.

Is it dangerous to take too many electrolytes?

In a healthy adult, the kidneys eliminate the excess, and the main risk remains digestive: a too concentrated drink slows gastric emptying and causes nausea and diarrhea during exercise. Two situations, however, require real caution. High blood pressure and low-salt diets, for which additional sodium intake should be discussed with a doctor. Kidney failure and treatments affecting potassium—certain diuretics, certain blood pressure medications—where potassium intake can pose a real problem. In these two cases, seek medical advice before using a hydration powder. Finally, let's remember the opposite risk, more common in practice: drinking large quantities of plain water without salt during a long effort exposes you to hyponatremia.

What is an electrolyte imbalance?

A discrepancy between the blood concentration of a mineral and its normal range—too much potassium, not enough sodium, and so on. This is a medical concept, which is determined by a blood test and not by sensations: the symptoms mentioned online, fatigue, cramps, palpitations, headaches, are too non-specific to conclude anything. The usual causes, moreover, have nothing to do with sport: vomiting, diarrhea, certain treatments, kidney diseases. For athletes, the most documented form is exertional hyponatremia described above. If you think you are affected, the answer is a consultation, not a drink.

Is water an electrolyte?

No. Water is the solvent; electrolytes are the minerals dissolved in it. Pure water, moreover, hardly conducts electricity.

What electrolyte drinks do we offer?

Our selection favors formulas where the nutritional table details mineral by mineral: Rule One's five-mineral formula, IO Genix's Hydra Train which combines electrolytes and amino acids, RAW Nutrition's hydration and TrainedByJP's.

For endurance, these products are combined with a fast carbohydrate source: cyclic dextrin, very well tolerated digestively, or maltodextrin for a more contained cost. EAAs are mixed in the same bottle, and taurine is already present in several of these formulas. For a simply flavored sugar-free drink outside of exercise, see Bolero drinks; for daily minerals, multivitamins and minerals.

Choosing your electrolytes in-store near Montpellier

In the Languedoc climate, the question is not theoretical: between June and September, the losses from a long outing around Montpellier have nothing to do with those from a session in an air-conditioned gym. In our store in Vendargues, about ten minutes from Montpellier, we compare labels line by line to see how much sodium each dose actually contains. We ship everywhere in France and Europe.

How much sodium, potassium, and magnesium are actually lost during exercise, and how to compensate for them without choosing the wrong drink: our guide to athlete hydration provides the key figures.

Sources: Regulation (EU) No 432/2012 for claim wordings and their conditions of use, EFSA for corresponding scientific opinions, ANSES for French nutritional guidelines.