Hiking, Running, and Active Vacations: Why Electrolytes Are More Important Than Water Alone in the Summer
Table of Contents
- Was sind Elektrolyte und welche Aufgaben haben sie im Körper?
- Die Mechanik des Schwitzens: Welche Nährstoffe wir wirklich verlieren
- Wasservergiftung: Warum reines Wasser beim Sport nicht reicht
- Die wichtigsten Elektrolyte für Ausdauer und Muskelfunktion
- Isotonisch, hypotonisch oder hypertonisch? Das richtige Sportgetränk
- Trink-Fahrplan: Wann und wie viel beim Sport trinken?
- Fazit: Elektrolyte – mehr als nur ein Profisportler-Thema
- Häufig gestellte Fragen zu Elektrolyten
- Literatur
Summer draws us outdoors – onto hiking trails, running routes or active holidays. Sweating is the body’s natural cooling mechanism. But with every drop of sweat, the body loses not only water, but also important minerals – known as electrolytes. Anyone who replaces these losses only with plain water risks reduced performance, muscle cramps and, in extreme cases, even a dangerous dilution of the blood.
In this guide, you will learn what electrolytes are, which minerals you lose when sweating, why plain water is often not enough during prolonged physical activity and how to replenish your mineral stores in a targeted way.
What are electrolytes and what roles do they play in the body?
Electrolytes are electrically charged minerals (ions) dissolved in body fluids such as blood, sweat and cellular fluid. Put simply: They are special salts that break down in water into positively or negatively charged particles. This charge is exactly what makes them so important, as it forms the basis for countless processes in the body.
Which minerals count as electrolytes?
The most important electrolytes in the human body include:
- sodium
- potassium
- calcium
- magnesium
- chloride
- phosphate
- bicarbonate
When it comes to sport, heat and sweating, the first four are especially relevant: sodium, potassium, calcium and magnesium.
Electrolytes are absorbed through the daily diet, for example through fruit, vegetables, whole grain products, dairy products, mineral water and the salt in meals.
They are excreted mainly via the kidneys, in smaller amounts through the stool – significantly more in the case of diarrhea – and through sweat. Because this cycle of intake and excretion runs continuously, electrolytes must be replenished daily – and correspondingly more on hot summer days or during physical exertion.
What tasks do electrolytes perform?
Electrolytes are involved in practically every basic function of the body. Their most important tasks are:
- Regulating fluid balance: They control how much water is inside and outside the cells.
- Transmitting nerve impulses: Without the regulated exchange of sodium and potassium at nerve cells, nerve signaling would not be possible.
- Controlling muscles: Calcium triggers muscle contraction, while magnesium enables subsequent relaxation.
- Stabilizing the acid-base balance: Electrolytes help keep the blood pH within a narrow normal range.
- Regulating blood pressure and heart rhythm: Sodium, potassium and magnesium in particular influence cardiovascular function.
If electrolytes get out of balance – for example through heavy sweating, diarrhea or one-sided drinking of plain water – the whole system can become unstable. This is exactly why it is worth taking a closer look, especially during sport in summer.
The mechanics of sweating: Which nutrients we really lose
Sweating is a central part of thermoregulation: When sweat evaporates on the skin, it draws heat away from the body. This keeps body temperature stable despite exertion or heat. But sweat is not just water. It contains dissolved minerals – above all sodium and chloride, and in smaller amounts also potassium, calcium and magnesium.
How much sweat is really produced in summer?
Sweat rates while hiking in the sun or running in the heat can reach 0.5 to 1.5 liters per hour, and significantly more during intense exercise in extreme heat. Authors of an older but still frequently cited review give the practical rule of thumb to drink 150 to 300 milliliters every 15 to 20 minutes to compensate for losses.
Which electrolytes are found in sweat?
How much sweat a person produces and which minerals it contains in what amounts varies greatly from person to person.
Factors include:
- predisposition (genetics)
- diet
- how long and how intensely one exercises
- how heavily one sweats
- how well the body is adapted to heat
The following table provides a rough guide to how many minerals can be lost per liter of sweat. The values vary greatly between individuals, but show the relative proportions of the individual electrolytes:
| Electrolyte | Content in sweat per liter | Note |
| Sodium | 230–2,070 mg | Largest share, varies greatly between individuals |
| Chloride | 355–3,195 mg | Accompanies sodium |
| Potassium | 80–315 mg | Smaller amount, but relevant |
| Calcium | 8–80 mg | In smaller amounts |
| Magnesium | under 10 mg | Small share |
Some people are so-called “salty sweaters” – their sweat leaves visible white salt marks on clothing and skin. They lose above-average amounts of sodium and should pay particular attention to replacement.
In practice, this means: Anyone who is active in heat for longer than one hour will lose enough electrolytes that plain water without minerals will not restore balance.
Water intoxication: Why plain water is not enough during sport
Plain water may quench thirst, but during prolonged exertion it can paradoxically become a problem. Anyone who drinks only low-sodium tap or table water can even promote a condition doctors call hyponatremia – an excessively low sodium concentration in the blood.
The background is this: If a lot of sodium is lost through sweat and, at the same time, large amounts of low-sodium fluid are consumed, the sodium level in the blood is diluted even further.
Possible signs of exercise-associated hyponatremia include:
- dizziness and nausea
- headaches
- noticeable drop in performance
- muscle cramps and muscle weakness
- confusion and concentration problems
- bloated feeling, swollen hands or feet
In severe cases, pronounced hyponatremia can also lead to dangerous water accumulation in brain tissue. Researchers have observed this especially in marathon runners, ultrarunners and mountain hikers who drank large amounts of water over long periods.
Important to know: Hyponatremia is not the same as classic dehydration due to fluid deficiency. Both conditions can have similar symptoms – but the cause and the correct response are different. In the case of persistent or severe symptoms, medical evaluation is therefore always important.
The most important electrolytes for endurance and muscle function
During sport and heat exposure, certain electrolytes become especially important because they play a central role in muscle work, nerve function and fluid balance. Anyone who sweats regularly should therefore know which minerals should be specifically replenished – because each one performs its own, irreplaceable tasks in the body. Four electrolytes are particularly relevant: sodium, potassium, calcium and magnesium.
Sodium and potassium: Regulators of fluid balance
Sodium and potassium are the most important regulators of osmotic pressure in the body. Put simply, they determine where water flows in the body and where it remains bound. Sodium is mainly active in the space outside the cells – that is, in blood and tissue fluid. Potassium, on the other hand, dominates inside the cells.
Both minerals work closely together:
- Sodium draws water out of the cell and is crucial for blood volume and blood pressure. If more sodium is excreted and not replaced, blood volume can decrease.
- Potassium is important for muscle function because it is involved in transmitting electrical signals between nerves and muscle cells. In addition, potassium contributes to the function of the nervous system and to maintaining blood pressure.
If the ratio of these two electrolytes shifts, this can impair muscle work and overall performance perception.
Calcium – the underestimated pacemaker of muscle work
Calcium is not only a building block of bones, but also directly involved in every muscle contraction: When a nerve impulse reaches the muscle cell, calcium ions are released and trigger contraction of the muscle fibers. Only when calcium is pumped back into its stores can the muscle relax again. Without calcium, neither targeted movement nor a stable heartbeat would be possible.
Compared with sodium, only small amounts of calcium are excreted through sweat. During long periods of exertion or a multi-day active holiday, however, these losses add up.
An adequate calcium supply through the diet is therefore all the more important. If too little calcium is absorbed, the body draws on its largest calcium stores: the bones. A needs-based intake therefore supports not only muscle and nerve function, but also protects bone substance.
Magnesium: Partner for muscles and energy metabolism
Magnesium is involved in more than 300 enzymatic reactions in the body. During sport, it performs several central tasks at once: Magnesium contributes to electrolyte balance and is important for normal muscle function – it is involved in relaxing muscles after contraction. Magnesium and calcium therefore act as natural counterparts in the muscle cell.
In the nervous system, the body’s own magnesium also acts like a natural brake: It regulates the excitability of nerve cells and helps dampen excessive signal transmission.
In addition, magnesium supports energy metabolism: As a cofactor, it is involved in the formation of ATP – the energy-rich molecule that muscle cells need for every contraction.
Anyone who wants to supplement magnesium via a preparation can choose between different compounds. Which one is particularly suitable for everyday life and sport depends on various factors – more on this in the guide “Which magnesium is best? Forms, bioavailability and recommendation”.
Isotonic, hypotonic or hypertonic? The right sports drink
Isotonic drinks are considered classics among sports drinks. But what does isotonic mean – and is this form really always the best choice?
The term “isotonic” refers to the osmotic pressure of the drink compared with blood plasma. This determines how quickly the fluid is absorbed from the intestine into the blood – and whether a drink initially supplies the body with water or may even temporarily draw water from it.
Three categories are distinguished:
| Drink type | Osmolarity | Absorption in the intestine | Typical examples |
| Hypotonic | Lower than blood | Very fast | Water, heavily diluted juice spritzers |
| Isotonic | Same as blood | Fast | Special sports drinks, well-balanced electrolyte solutions |
| Hypertonic | Higher than blood | Delayed | Lemonades, cola, undiluted juices, many colorful sports drinks |
In practice, this means: Isotonic drinks are often the best choice for endurance sports because they quickly compensate for both fluid and electrolyte losses. Hypotonic drinks are absorbed particularly quickly, but provide only few minerals. Hypertonic drinks, on the other hand, can initially draw water from the body in the intestine because they first have to be diluted to an absorbable concentration.
Apple spritzer myth: Is the classic juice spritzer enough as a sports drink?
An apple spritzer in a 1:3 ratio (juice to water) is an acceptable basic drink and contains some potassium from the apple juice. During intense sweating, however, it provides far too little sodium, as this is practically absent from apple juice. Anyone active in heat for longer than one hour – for example mountain hiking – is better served by a targeted electrolyte mix that accurately reflects the sodium-potassium ratio without supplying unnecessary sugar.
Why colorful sports drinks are often the problem
Classic sports drinks from the supermarket often contain 6 to 8 grams of sugar per 100 milliliters and are therefore hypertonic. Instead of hydrating quickly, the sugar load burdens the stomach, which can lead to nausea in heat and during exertion.
A sugar-free electrolyte preparation in powder or capsule form is often the more thought-out choice here: It contains the important minerals in a balanced amount – without sweeteners, artificial flavors or unnecessary additives.
FormMed tip – the right electrolyte preparation
For reliable electrolyte supply during sport or on hot summer days, FormMed has developed a sugar-free electrolyte preparation that provides the most important minerals – including sodium, potassium and magnesium – in a balanced ratio. A solution that can be used easily on active holidays, during sport or on sweaty summer days.
Drinking plan: When and how much should you drink during sport?
The right fluid and mineral supply does not start during sport, but before it. A good strategy rests on three pillars: preparation, supply during exertion and replenishment afterwards.
The goal is not to drink as much as possible, but according to need – a well-planned drinking strategy helps prevent performance losses, muscle cramps and mineral losses.
Drinking plan: hiking, running and cycling
- Before activity: Drink around 400–500 milliliters of fluid about 1–2 hours beforehand, ideally mineral-rich water or an isotonic solution.
- During activity: Especially during activities lasting over 60 minutes, drink small sips every 15–20 minutes (100–200 milliliters). In case of heavy sweating or heat, electrolytes should be included.
- After activity: Compensate for fluid loss within the first 1–2 hours – ideally with electrolytes to also replace sweat losses. A rough guide is about 500–750 milliliters per hour of exertion. Anyone who wants to know exactly can weigh themselves before and after exercise: For every kilogram of weight lost, about 1.5 liters of fluid should be consumed.
Two situations deserve special attention:
- On hot days: Drinking more throughout the day helps prevent a deficit from developing in the first place. Mineral-rich water or an electrolyte-containing solution is a better choice than plain tap water.
- On mountain tours or long hikes: Use breaks actively for drinking instead of waiting until you feel thirsty. A sugar-free electrolyte mix in your backpack specifically compensates for mineral losses on the go.
Conclusion: Electrolytes – more than just a topic for professional athletes
Electrolytes are not only a topic for high-performance athletes, but concern everyone who is active in summer – from hikers on alpine tours to recreational runners. The minerals regulate fluid balance, control muscle work and transmit nerve impulses. Anyone who sweats for a longer period loses not only water, but also important minerals – above all sodium and potassium, as well as small amounts of calcium and magnesium.
Plain water alone is often not enough in such situations: Anyone who drinks large amounts of low-sodium fluid without compensating for mineral losses can further disrupt the water-mineral balance – in extreme cases leading to exercise-associated hyponatremia.
The key is therefore needs-based supply: drink enough, but with the right ingredients and at the right timing. Colorful, sugary sports drinks from the supermarket are rarely the best choice. High-quality, sugar-free electrolyte preparations provide the important minerals in a balanced amount – ideal for sport, active holidays and sweaty summer days.
Frequently asked questions about electrolytes
Supplementing electrolytes is especially useful when the body loses larger amounts through sweat – for example during intense sport, long hikes, heat or sauna sessions.
The need can also increase during illnesses with high fluid loss such as diarrhea or vomiting. In everyday life with moderate activity and a balanced diet, the normal diet usually covers the requirement.
Typical symptoms of an electrolyte deficiency include muscle cramps, fatigue, dizziness, poor concentration, headaches or a “queasy” feeling during sport.
Since these symptoms are nonspecific, medical evaluation is advisable if they occur frequently or persist for a longer period.
Classic sore muscles are caused by small injuries in the muscle fibers and not primarily by mineral deficiency. Electrolytes therefore do not directly help against sore muscles.
However, a good supply is important to prevent deficiency – because muscle cramps are associated in research with a disturbed electrolyte balance.
A very quick way to get electrolytes is through isotonic electrolyte solutions or targeted electrolyte preparations.
Sodium-rich mineral water as well as mineral-rich foods such as bananas (potassium), a clear broth (sodium) or nuts (magnesium) can also contribute to short-term replacement.
Yes, overdosing is possible – especially with sodium and potassium. Anyone using electrolyte preparations should follow the manufacturer’s recommended intake.
In cases of kidney disease, high blood pressure or certain medications such as diuretics or ACE inhibitors, intake should additionally be discussed with a doctor.
No. “Isotonic” describes the osmotic pressure of a drink. “Electrolytes” are the minerals it contains.
An isotonic drink usually contains electrolytes. But not every electrolyte-containing drink is automatically isotonic.
Classic isotonic drinks are specially formulated sports drinks and electrolyte solutions with a mineral and carbohydrate concentration matched to blood plasma.
A homemade apple spritzer in a 1:3 ratio (one part juice, three parts water) can also fall within the isotonic range. However, it is usually low in sodium and does not replace a targeted sports drink during prolonged exertion in the heat.
An isotonic drink has the same osmotic pressure as blood plasma and is therefore absorbed particularly quickly by the body. It supplies both fluid and minerals in one step, which makes it practical especially during longer periods of exertion or on hot days.
While isotonic drinks are absorbed quickly by the body, hypertonic drinks are more concentrated – for example due to a lot of sugar. They are absorbed more slowly in the intestine and can even temporarily draw water from the body because they first have to be diluted to an absorbable concentration.
Alcohol-free wheat beer is often promoted as a sports drink because it contains potassium, magnesium and some B vitamins. However, the sodium content is very low – a disadvantage in the case of high sweat losses.
It can be suitable as an occasional addition; however, it does not replace a targeted electrolyte drink during prolonged exertion.
During diarrhea, the body mainly loses sodium, potassium and water.
Targeted replacement with a specially formulated electrolyte solution is therefore important. Classic solutions also contain glucose because it supports sodium absorption in the intestine – sugar-free variants are also suitable. More on this in the guide on diarrhea.
Literature
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