Electrolytes: when you need them and how to choose
Electrolytes are minerals that act as salts in the body: sodium, potassium, chloride, magnesium and calcium. They help regulate the amount of water in the body, as well as muscle and nerve activity.
In this article you will learn when electrolyte drinks are really useful, when water is enough, and how to find the most important numbers on the label.
In brief. For most people, water and a varied diet are enough day to day, because food also provides electrolytes. Electrolyte drinks are especially useful during long and intense exercise, on hot days, or after losing a lot of fluid, for example when you are ill.1 During a long workout or hike, it is worth drinking more than just water: also replace the salts lost through sweat so that your body's balance stays good.2
What do electrolytes do?
| Electrolyte | What it is needed for | Where it is found |
|---|---|---|
| Sodium | The main electrolyte lost in sweat.1 | Salt, bread, cheese, processed foods |
| Potassium | Contributes to normal muscle function, to the normal functioning of the nervous system and to the maintenance of normal blood pressure.3 | Potatoes, bananas, pulses, vegetables |
| Magnesium | Contributes to electrolyte balance and to normal muscle function.3 | Nuts, seeds, wholegrain products |
| Calcium | Contributes to normal muscle function.3 | Dairy products, fortified plant-based drinks |
We usually get more sodium than we need. For adults, 2 g of sodium per day is safe and adequate, i.e. about 5 g of salt.4
When are electrolytes needed?
- Long or intense exercise. When the effort lasts longer than an hour, especially if you sweat a lot.1
- Heat. You sweat more when working or exercising in the heat.1
- Diarrhoea or vomiting. A lot of fluid and salts are lost. In this case, rehydration solutions sold in pharmacies are the most suitable.5
When water is enough. If you exercise for 30–45 minutes at a moderate pace, water and ordinary food after your workout are usually enough.
Example. Weigh yourself before and after a workout. If your weight has dropped by more than 2%, you drank too little during the workout.1 For a person weighing 70 kg, that is more than 1.4 kg.
Is it possible to drink too much water?
Yes. If you drink a very large amount of plain water during prolonged exertion, the sodium level in your blood can drop too low. In a study of 488 marathon runners, this happened to 13% of participants. It most often affected those who drank so much while running that they weighed more at the finish than at the start.2
What this means for you. Drink according to thirst and sweating, not by the rule "the more, the better". In long competitions, choose a drink containing sodium.
How to choose an electrolyte product?
- Look at the sodium content. This is the most important number. Electrolyte products contain from 150 to 600 mg per serving.
- With or without carbohydrates. Drinks with carbohydrates are useful during long workouts. Carbohydrate-electrolyte solutions of suitable composition contribute to the maintenance of endurance performance during prolonged endurance exercise and enhance the absorption of water during physical exercise.3 For shorter workouts or everyday use, sugar-free products are suitable.
- Other ingredients. Some products contain vitamins, plant extracts or amino acids. If you take other supplements, add up the amounts.
Example. If a serving contains 300 mg of sodium and you dissolve it in 500 ml of water, a litre of the drink will contain 600 mg of sodium. If you drink 2 servings, you get 600 mg of sodium – roughly the amount found in 1.5 g of salt.
Who should be careful?
- You have kidney or heart disease.
- Your doctor has recommended limiting salt because of high blood pressure.
- You take medicines that lower blood pressure or increase urine output. Discuss potassium supplements and electrolyte drinks containing potassium with your doctor.6
Selected electrolyte products
Commercial information. The products listed here are available in our shop. This is not a ranking of effectiveness. Before buying, check the composition and instructions for use on the product page.
Electrolyte Hydrate, Lemon Lime - 300g - Stacker2 Europe
Sugar-free. Each serving (7.5 g) contains 300 mg of sodium, 150 mg of potassium, 56 mg of magnesium and 40 mg of calcium, as well as 5 mg of zinc and vitamin B6. Dissolve in 400–500 ml of water.7
Joe Weider Victory Endurance Salt, Citrus - 15 effervescent tablets - Weider
Effervescent tablets. Each serving (2 tablets) contains 606 mg of sodium, 204 mg of calcium, 130 mg of potassium, 16 mg of magnesium and B vitamins. High in sodium, so better suited to long exertion in the heat.8
Joe Weider Victory Endurance Iso Energy, Lemon - 900g - Weider
Carbohydrate and electrolyte drink. Each serving (30 g with 420 ml of water) contains 26 g of carbohydrates, 347 mg of sodium, 313 mg of calcium and 165 mg of magnesium. Designed for long endurance workouts.9
Hydration Powder, Wild Berry - 180g - Weider
No added sugar. Each serving (6 g with 300 ml of water) contains 150 mg of sodium, 120 mg of potassium, 80 mg of magnesium and 60 mg of calcium, as well as taurine and plant extracts. The lower sodium content suits shorter workouts.10
Frequently asked questions
Can electrolytes be taken every day?
If you do not exercise for long periods and do not sweat in the heat, you usually do not need them. We get enough sodium from food.4
Do electrolytes help with cramps?
Electrolyte drinks often contain potassium, magnesium or calcium. These substances contribute to normal muscle function, so it is worth replenishing them during a long workout or on a hot day. However, cramps during exercise can have various causes, for example fatigue, overexertion or an insufficient warm-up, and not only a lack of fluids and salts. If cramps keep recurring, talk to your doctor or a sports professional.
What other supplements are useful for exercise?
We write more about this in the article Supplements for people who exercise.
Scientific sources
- American College of Sports Medicine; Sawka MN, Burke LM, Eichner ER et al. Exercise and fluid replacement. Med Sci Sports Exerc. 2007;39(2):377–390. doi:10.1249/mss.0b013e31802ca597
- Almond CSD, Shin AY, Fortescue EB et al. Hyponatremia among runners in the Boston Marathon. N Engl J Med. 2005;352(15):1550–1556. doi:10.1056/NEJMoa043901
- Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods (consolidated version). EUR-Lex
- EFSA NDA Panel. Dietary reference values for sodium. EFSA Journal. 2019;17(9):5778. doi:10.2903/j.efsa.2019.5778
- NHS. Dehydration. nhs.uk
- NIH Office of Dietary Supplements. Potassium – Fact Sheet for Health Professionals. ods.od.nih.gov
- Stacker2 Europe. Electrolyte Hydrate, Lemon Lime, 300 g. Product label.
- Weider. Victory Endurance Salt, Citrus, 15 tablets. Product label.
- Weider. Victory Endurance Iso Energy, Lemon, 900 g. Product label.
- Weider. Hydration Powder, Wild Berry, 180 g. Product label.
Disclaimer. This article is for informational purposes only and does not replace a consultation with a doctor or pharmacist. Food supplements are not intended to treat or prevent diseases and are not a substitute for a varied diet and a healthy lifestyle. Before taking supplements, especially during pregnancy or breastfeeding, if you have a chronic illness or if you take medicines, consult a healthcare professional.
