Electrolyte Drinks: When You Actually Need Them

Electrolyte Drinks: When You Actually Need Them

Over the past couple of years electrolyte drinks have moved from the gym shelf into ordinary kitchens. Part of that is justified and part of it is marketing. If you train for an hour four times a week in a cool gym, you are not losing anything in sweat that normal food and water would not cover. If you run for two hours in July, do CrossFit in a hot room, or head to the sauna after training, the situation is different.

This article tries to draw that line. We look at what electrolytes actually do in the body, how much sodium is really lost in sweat, when water is entirely sufficient, what a serving costs in Estonia, and who should not be reaching for an electrolyte drink at all. Prices come from the MaxFit range at the time of writing.

What electrolytes actually do

Electrolytes are simply minerals that separate into charged particles in water: sodium, potassium, chloride, magnesium, calcium. Their job is not "giving energy" but maintaining the voltage difference across cell membranes. Nerve impulses, muscle contraction and the distribution of fluid inside and outside cells all depend on it.

In practice that means three things for someone who trains. First, sodium is the only electrolyte lost in sweat in a clinically meaningful amount. Second, losses of potassium, magnesium and calcium through sweat are small and covered by an ordinary diet. Third, sodium's role is not only to replace what was lost — sodium keeps the fluid you drink in the body, which is why a salty drink rehydrates better than plain water (Shirreffs et al., 1996).

That last point is the heart of the topic. The purpose of an electrolyte drink is usually not "treating a mineral deficiency" but making sure the water stays in you rather than going straight through within the hour.

How much sodium is really lost in sweat

The numbers here vary far more than any product label admits. Sweat sodium concentration varies roughly fivefold between individuals and also depends on sweat rate, heat acclimatisation and dietary salt intake (Baker, 2017). Two people training side by side in the same room can lose very different amounts of salt per hour.

A practical range: sweat sodium typically falls somewhere between about 20 and 80 mmol/l, and sweat rates run 0.5-2.0 litres per hour. Multiply those out and an hour of training gives a sodium loss somewhere between a couple of hundred milligrams and about two grams. The upper end is a serious amount; the lower end is one sandwich.

How to tell which end you are on without a laboratory: if a dark shirt dries with white salt streaks after a long session and sweat stings your eyes badly, you are probably a higher sodium loser. If the shirt dries clean, you are not. It is not precision science, but it is a better guide than the text on the packaging.

When water is entirely sufficient

For most sessions by most people training in Estonia, water is enough. More specifically:

• Sessions under 60 minutes in a cool room. Sodium loss is small and the next meal covers it without any effort.
• A regular gym session, where heart rate is low for most of the time and real sweating only starts in the last third.
• Walking, easy cycling, swimming — you do sweat while swimming, but you rarely notice it and the duration is usually short.
• An office day. A tub of electrolyte powder on your desk does not improve focus if you are already drinking enough water.

The American College of Sports Medicine position stand makes the same point: adding electrolytes matters with longer duration, heat and repeated sessions, not at every workout (Sawka et al., 2007).

When an electrolyte drink is justified

Four situations where it is not marketing:

Continuous effort over 90 minutes. A long run, a marathon, a long ride, a hockey game, a tournament day. Here both fluid and sodium losses are large enough that water alone starts to disturb fluid balance.

Heat. A 28-degree July day in Estonia is exactly this kind of situation, all the more so because we are not heat-acclimatised. An unacclimatised person loses more sodium in sweat than the same person at the end of August.

Two sessions in one day. A morning and an evening session on the same day leaves a short recovery window in between. A salty drink restores fluid balance faster than water alone (Shirreffs et al., 1996).

Sauna after training. This one is Estonia-specific but entirely real. Two ten-minute rounds after an hour of training can add half a litre or more of sweat loss, which people usually leave out of the calculation because they do not count the sauna as training.

Illness and hangover. When fluid is lost through vomiting or diarrhoea, oral rehydration makes sense — although then a pharmacy rehydration sachet is the right choice rather than a sports drink. We have written up that distinction in electrolytes at the pharmacy.

Product comparison

Concretely: OstroVit Pure Electrolytes 270g costs 10.90 EUR at the time of writing and is an unflavoured powder you can dose yourself. OstroVit Electrolyte 20tabs Apelsin is 4.90 EUR and the simplest thing to leave in a bag or a car. PowerBar Iso Active 600g Sidrun (18.90 EUR) is a classic isotonic powder with carbohydrate, built for long efforts rather than for a desk. XTEND Original Amino Acids 30 servings Arbuus (27.90 EUR) is an amino acid drink that also contains electrolytes — sensible if you already drink aminos during training, less so if all you want is salt.

How to read a label without a chemistry degree

Electrolyte labels are written so the number looks big. Three places to pay attention.

Sodium versus salt. Some manufacturers state sodium, others sodium chloride, that is, salt. One gram of salt contains about 400 mg of sodium. So "1000 mg of electrolytes" on the front does not mean 1000 mg of sodium and probably does not mean even half of that.

Serving size. The same trick as on protein powders: the table is often per 100 grams while a serving is 7 grams. Find the "per serving" column and work out how many servings the tub really holds. Two tubs at 10.90 and 14.90 EUR can produce exactly the opposite cost per serving to what the front of the pack suggests.

Mineral form. Citrates and glycinates dissolve better and are gentler on the stomach than oxides. Magnesium oxide in a cheap powder gives the label a nice number but is absorbed modestly. If a powder upsets your stomach, changing the form is a more sensible step than cutting the dose.

Added vitamins. Many electrolyte blends include B vitamins or vitamin C. They do no harm, but they are not a reason to pick a product — if you want vitamin coverage, a separate complex is cheaper and more precise.

The practical conclusion: always compare products on one number, milligrams of sodium per finished litre of drink. Everything else on the label is flavour, convenience or sales copy.

Sugar in the drink: when it is a feature, not a flaw

This is where people go wrong most often. A classic isotonic drink contains 6-8% carbohydrate, and that is not an accident — that concentration empties from the stomach at a reasonable rate and provides fuel during a long effort. For endurance work, carbohydrate intake during exercise sits in the region of 30-60 grams per hour (Jeukendrup, 2014).

If your session is an hour in the gym, you do not need that fuel and an isotonic drink is simply a sweet drink. If your session lasts three hours, a sugar-free electrolyte tablet is an incomplete solution, because you get the sodium but not the energy.

A rule that mostly works: under 90 minutes, sugar-free or just water. Over 90 minutes, a carbohydrate-containing drink. On carbohydrate sources, and where maltodextrin genuinely makes sense, we have written separately in maltodextrin in sport.

Drinking too much is more dangerous than drinking too little

This gets far too little airtime. In endurance sport the main acute fluid problem is not dehydration but the opposite: drinking a large volume of low-sodium fluid and diluting blood sodium. The international consensus statement describes this as exercise-associated hyponatremia and stresses that overdrinking is the primary risk factor (Hew-Butler et al., 2015).

The practical conclusion: do not drink as much as you can "just in case". Drink to thirst and add sodium when duration or heat justifies it. A meta-analysis of endurance performance also showed that moderate exercise-induced fluid loss impairs performance less than was once assumed (Goulet, 2011). The body tolerates a small deficit well; what it tolerates badly is rapid dilution.

The Estonian context: winter, sauna and gym air

Three local details international guidelines do not cover.

Dry indoor air in winter. From December to March most of us train indoors where humidity is low. Sweat evaporates fast, so it feels as though there is no sweating. The sweating is still there, just invisible. This is the most common reason fluid intake is underestimated in winter.

Sauna. As noted above, a sauna after training is an entirely normal Estonian routine, and in sweat terms it is an extra session. If you go to the sauna, that is precisely the situation where a salty drink afterwards makes more sense than a glass of water.

Dietary salt. The Estonian table tends to carry plenty of salt rather than too little. That means the average person is not sodium-deficient at rest, and electrolyte powder "for general wellbeing" is not justified. Sodium is useful in a training context, not deficient in an everyday one.

The start of the outdoor season. In April and May, when training moves outside and the first warm days arrive unexpectedly, people are at their least acclimatised. The same pace that felt easy in March produces a considerably higher sweat rate in May. Those first two weeks outdoors are the one period of the year when electrolytes are worth considering even for a medium-length session, because acclimatisation takes roughly that long.

Who should skip electrolyte drinks

• Anyone with high blood pressure or kidney disease. Adding sodium should then be a doctor's call, not a shop's recommendation.
• Anyone drinking them daily at a desk with no training. That is flavoured salt water whose only certain effect is on your wallet.
• Anyone looking for a fix for night-time cramps. The link between cramps and electrolytes is far weaker in the literature than folk wisdom suggests; cramps are more often related to muscle fatigue and neuromuscular control.
• Anyone in a calorie deficit reaching for a sweet isotonic drink before a short strength session. That is 120 calories you did not plan for.
• Children in normal training. Water and normal food cover it.

A practical protocol

1. Under 60 minutes, cool room: water. Nothing else.
2. 60-90 minutes or a warm room: water during the session, a salty meal or one electrolyte tablet afterwards.
3. Over 90 minutes, heat, or a second session the same day: 300-600 mg of sodium per litre of drink, plus carbohydrate for long efforts.
4. After a hard session with a sauna: drink about 1.2-1.5 times the weight lost, and make it salty rather than plain.
5. Weigh yourself before and after one session to learn your real sweat rate. One measurement tells you more than a year of guessing.
6. More precise timing — before, during or after — is worked through in when to take electrolytes.

The full electrolyte range sits under electrolytes. If recovery is handled but daily protein is short, proteins is the more effective first purchase, and for general coverage it is worth looking at vitamin complexes.

FAQ

Do electrolyte drinks help with a hangover?

They do replace fluid and sodium, but they do not speed up alcohol metabolism. If fluid loss has been large, a pharmacy rehydration sachet is a better choice than a sports drink.

Do I need electrolytes at every training session?

No. For sessions under an hour in a cool room, water and your next meal are enough.

Does magnesium in the drink relieve cramps?

The evidence is weak. Cramps are mostly related to fatigue and to how much load the muscle can tolerate, not to magnesium deficiency. Take magnesium if your diet falls short, not as a cramp treatment.

Can I store electrolyte powder in the car or a bag?

Effervescent tablets handle that best because each one is individually protected. Loose powder draws moisture and clumps, especially when the tub moves between warm and cold. If you keep a reserve in your training bag, choose the tablet form.

Does a homemade mix work?

Yes, technically. A litre of water, about a quarter teaspoon of salt and a little juice for flavour gives roughly the right sodium content. The drawbacks are taste and the fact that nobody bothers to make it a third time.

How much sodium should a drink contain?

For long efforts, 300-600 mg of sodium per litre is a sensible range. Very salty sweaters need the upper end; most people need the lower.

Is sugar-free always better?

No. For a short session yes; for a long effort no — there the carbohydrate is the point of the drink, not an additive.

References

Baker, L. B. (2017). Sweating rate and sweat sodium concentration in athletes: a review of methodology and intra/interindividual variability. Sports Medicine, 47(Suppl 1), 111-128. https://pubmed.ncbi.nlm.nih.gov/28332116/

Goulet, E. D. B. (2011). Effect of exercise-induced dehydration on time-trial exercise performance: a meta-analysis. British Journal of Sports Medicine, 45(14), 1149-1156. https://pubmed.ncbi.nlm.nih.gov/21454440/

Hew-Butler, T., Rosner, M. H., Fowkes-Godek, S., et al. (2015). Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Clinical Journal of Sport Medicine, 25(4), 303-320. https://pubmed.ncbi.nlm.nih.gov/26102445/

Jeukendrup, A. E. (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine, 44(Suppl 1), S25-S33.

Sawka, M. N., Burke, L. M., Eichner, E. R., et al. (2007). American College of Sports Medicine position stand. Exercise and fluid replacement. Medicine & Science in Sports & Exercise, 39(2), 377-390.

Shirreffs, S. M., Taylor, A. J., Leiper, J. B., & Maughan, R. J. (1996). Post-exercise rehydration in man: effects of volume consumed and drink sodium content. Medicine & Science in Sports & Exercise, 28(10), 1260-1271. https://pubmed.ncbi.nlm.nih.gov/8897383/