Electrolytes: When You Really Need Them and Which Ones to Choose

You're back from training, drenched in sweat. In the shop, you see half a shelf of colourful drinks labelled "electrolytes", "hydration", "recovery". They cost a small fortune. At the pharmacy - powders "for electrolyte replenishment". A runner friend says they make their own electrolytes at home. And you're standing there wondering: do I even need this?

Marketing has turned electrolytes into a trend. Everyone drinks them, nobody really knows why. So today let's be honest: when do you really need electrolytes, and when is plain water perfectly sufficient? And what to choose so you're not overpaying for coloured sugar water.

What exactly are electrolytes?

Let's start with the basics. Electrolytes are minerals that conduct electrical current when dissolved. Sounds like physics? In practice, these are substances essential for basic bodily functions.

The most important electrolytes are:

• Sodium (Na+) - the main electrolyte in extracellular fluids, regulates blood pressure, water balance
• Potassium (K+) - crucial for muscle function (including the heart!) and the nervous system
• Chloride (Cl-) - works with sodium, important for acid-base balance
• Magnesium (Mg2+) - essential for over 300 enzymatic reactions, muscle function
• Calcium (Ca2+) - not just bones - also muscle contraction, nerve conduction

What do they do in the body?

Electrolytes are responsible for:

• Regulating the amount of water in and around cells
• Blood pH balance
• Conducting nerve impulses
• Muscle contraction (including the heart!)
• Kidney function

The body maintains their concentration within very narrow limits. If electrolytes drop too low or rise too high - problems appear. From muscle cramps to serious heart rhythm disturbances.

When do you lose electrolytes?

A healthy body regulates electrolyte levels through the kidneys, skin, and digestive tract. But there are situations when we lose more than usual.

1. Sweat (physical exercise, heat)

When sweating, you primarily lose water, but also sodium and chloride. To a lesser extent, potassium and magnesium.

How much do you lose? On average, 0.5-1 litre of sweat per hour of moderate exercise. In heat or during intense training - up to 2-3 litres per hour. Sweat contains about 500-1000 mg of sodium per litre.

2. Diarrhoea and vomiting

Here you lose enormous amounts of water and electrolytes - primarily sodium, potassium, and chloride.

Why is it serious? During acute diarrhoea (e.g., food poisoning, rotavirus), you can lose several litres of fluid per day. This leads to dehydration and electrolyte imbalances - especially in children and the elderly.

3. Diuretic medications

If you take blood pressure medications (e.g., furosemide, hydrochlorothiazide), you lose more sodium, potassium, and magnesium through urine.

4. Gastrointestinal diseases

Coeliac disease, Crohn's disease, irritable bowel syndrome - can disrupt electrolyte absorption.

5. Low-carbohydrate diet (keto)

The first weeks of keto cause water and sodium loss (the body stops storing glycogen, which binds water).

When is plain water enough?

Good news here: in most everyday situations, you don't need electrolytes. Plain water is perfectly sufficient.

Water is enough if:

• You exercise lightly to moderately, for less than 60-90 minutes
• You don't sweat excessively
• You eat regular meals (they provide sodium and potassium)
• You're healthy and don't take diuretic medication

A walk, yoga, a short run, 45 minutes of strength training? Water.

Normal daily activities? Water + a normal meal.

You don't need to "replenish electrolytes" every time you leave the house. The body manages perfectly well.

When are electrolytes genuinely needed?

OK, now the situations when water alone isn't enough.

1. Exercise lasting more than 90 minutes in heat

A marathon, a long bike ride, 2 hours of tennis in the sun - here you lose a lot of sodium. If you only replace water, you can dilute the blood (hyponatraemia - low sodium levels). Symptoms? Nausea, headache, disorientation. In extreme cases - life-threatening.

What to do: Drink isotonic beverages or water + a salty snack (banana, pretzel).

2. Diarrhoea and vomiting

Here electrolytes are crucial. Drinking water alone may not be enough - you need sodium and potassium so the body can absorb and retain the water.

What to do: Oral rehydration solutions (available at pharmacies). They contain the optimal ratio of glucose and sodium that supports water absorption in the intestines.

3. Heavy sweating in hot weather (without exercise)

Working outdoors in the heat? Heatwave and sweating all day? You may need extra sodium.

What to do: Drink water + eat normal, salty meals. You don't need to buy special drinks.

4. Keto diet in the first weeks

The body loses more sodium and water. Symptom? "Keto flu" - headache, fatigue, dizziness.

What to do: Increase sodium intake (broth, salty snacks) and magnesium.

Sports drinks vs oral rehydration solutions - they're not the same!

This is where confusion often arises. People buy Gatorade for diarrhoea or use oral rehydration solutions before training. That's a mistake.

Sports drinks (isotonic)

Typical composition (per 100 ml):

• Sodium: 40-50 mg
• Potassium: 10-20 mg
• Carbohydrates (sugars): 6-8 g

For whom: Athletes during prolonged exercise. Sugars provide energy, sodium replaces sweat losses.

Problem: Lots of sugar (25-30 g per bottle). If you drink this daily without training - it's just sweetened water.

Oral rehydration solutions (for diarrhoea)

Typical composition (per sachet dissolved in 200 ml of water):

• Sodium: 450-500 mg
• Potassium: 400-500 mg
• Glucose: 3-4 g

For whom: People with diarrhoea, vomiting, dehydration. The glucose-to-sodium ratio is optimal for water absorption in the intestines (cotransport mechanism).

Difference: More sodium and potassium, less sugar than sports drinks. The taste? Worse. But it's not about the taste.

Important: Don't drink oral rehydration solutions "for training" - too much sodium for sporting needs. And don't drink Gatorade for diarrhoea - too little sodium and potassium.

Is it worth making electrolytes at home?

Yes. It's cheaper and simpler than you think.

Recipe 1: Basic isotonic drink (sports)

Ingredients:

• 1 litre of water
• 2-3 tablespoons of lemon or orange juice
• 1-2 tablespoons of honey or sugar
• A pinch of salt (about 1/4 teaspoon = 500-600 mg sodium)

Mix and done. Cheap, simple, effective. The juice provides potassium and flavour, honey - carbohydrates (energy), salt - sodium.

Recipe 2: WHO rehydration fluid (diarrhoea)

Ingredients:

• 1 litre of boiled water
• 6 level teaspoons of sugar
• 1/2 level teaspoon of salt

Optional: Lemon or orange juice (for flavour and potassium).

Sip slowly every few minutes. If vomiting - take one teaspoon every 2-3 minutes.

Recipe 3: Coconut water - a natural isotonic

Coconut water (not milk!) naturally contains sodium, potassium, magnesium. Less sodium than sports drinks, but plenty of potassium.

For whom: Light to moderate exercise, recovery, post-workout replenishment.

Note: It won't replace rehydration solutions during acute diarrhoea (too little sodium).

What to buy at the pharmacy? A comparison

If you prefer ready-made options - here's what's worth knowing.

For diarrhoea and dehydration:

• Oral rehydration salts - classic, effective, affordable (about 3-5 EUR for 10 sachets)
• Various brands with lemon or berry flavour - similar composition, different taste
• Children's versions - with milder flavours

They all work the same - they differ in taste and price. Check the comparison on CheaperForDrug.

For sports:

• Isostar, Gatorade, Powerade - ready-made drinks. Expensive (2-3 EUR per bottle), lots of sugar.
• Powders to dilute (SIS, High5, Nutrend) - cheaper than ready-made drinks, less plastic.
• Effervescent tablets - convenient, but check the ingredients (some are mainly sugar and flavourings).

Magnesium and potassium supplements:

If you're prone to deficiencies (e.g., due to diuretic medication, lots of sport), you can supplement separately:

• Magnesium - citrate or bisglycinate, 200-400 mg daily
• Potassium - usually sufficient from food (bananas, potatoes, spinach). Only take potassium supplements under medical supervision (easy to overdo).

Sodium-potassium balance - why it matters

It's not just about having "enough" electrolytes. It's about the proportions.

The problem with the modern diet:

We eat too much sodium (salt in processed food) and too little potassium (not enough vegetables, fruits). This contributes to hypertension, heart problems.

Optimal ratio: About 1:2 (sodium:potassium). So if you eat 2000 mg of sodium per day, you should eat about 4000 mg of potassium.

Sources of potassium:

• Bananas (400 mg per banana)
• Potatoes (900 mg per medium potato)
• Spinach (800 mg per cup)
• Avocado (500 mg per half)
• Beans, lentils (700-900 mg per cup)

Eat vegetables and fruits regularly = no need to worry about potassium.

When too many electrolytes become a problem?

Yes, you can overdo it. Especially if you supplement unnecessarily.

Hyperkalaemia (too much potassium):

Symptoms: heart rhythm disturbances, muscle weakness, tingling.

Who is at risk: People with kidney problems, those taking potassium-sparing drugs (spironolactone).

Hypernatraemia (too much sodium):

Symptoms: thirst, confusion, seizures (in extreme cases).

When does it happen: Rarely - the body usually handles excess sodium well (it increases thirst, you excrete it in urine). But if you drink sea water or massively overdo salt with limited access to water - it can be a problem.

For most people, the problem is not excess, but too much sodium with too little potassium.

Practical tips

1. Don't drink "preventatively"

You don't need to drink electrolytes "in advance" before training. Drink water, eat normally. Replenish electrolytes during or after - if the training is long and intense.

2. Listen to your body

Muscle cramps, weakness, headache after training - may signal electrolyte deficiency. But they could also simply mean fatigue or dehydration. Try drinking water and eating something salty first.

3. With diarrhoea - don't wait

Dehydration develops quickly, especially in small children. If diarrhoea lasts more than a few hours - start giving rehydration fluids. In small portions, frequently.

4. Check what you eat

If you eat a lot of processed food (fast food, ready meals, cured meats) - you're probably getting too much sodium. If you eat few vegetables and fruits - too little potassium. Start by improving your diet, not with supplements.

5. Compare prices

Rehydration products can differ in price by up to 30-40% between pharmacies. Check CheaperForDrug before buying.

Summary - what to remember

Electrolytes are needed, but not in every situation. Most of the time, plain water + normal food is enough.

Exercising for more than 90 minutes in heat? Replenish sodium and carbohydrates (isotonic drinks or a homemade recipe).

Diarrhoea, vomiting? Oral rehydration solutions - not sports drinks!

You can make electrolytes at home - cheaper and without artificial additives. Water + lemon + honey + salt = a simple, effective drink.

Sodium-potassium balance matters - eat more vegetables and fruits, less processed food.

Don't drink electrolytes "preventatively" every day - the body doesn't need colourful drinks costing 2 EUR after a 30-minute walk.

Disclaimer

This information is for educational purposes and does not constitute medical advice. If you have kidney or heart problems, take diuretics, or other medications affecting electrolytes - consult your doctor about supplementation. Severe dehydration (especially in children) requires medical intervention.

Hydrate wisely, save even more wisely. Check rehydration product prices on CheaperForDrug - the same sachet could cost 50% less at the pharmacy next door.