Electrolytes: common myths examined

Few topics in sports nutrition are overgrown with as many "obvious truths" as electrolytes. Cramps are due to a lack of salt, thirst is a late signal, clear urine is ideal, and isotonic protects against all problems. The editors have checked these claims against research and position papers and tell you what is true and what is marketing or simplification.

Myth 1: cramps occur due to lack of salt and dehydration

This is probably the most common belief among runners and football players. The logic seems impeccable: sodium comes out with sweat, it builds up muscles, so it is necessary to "add salt". But prospective studies do not confirm this picture.

Schwellnus et al. (2011) followed 196 Ironman participants, measuring changes in body weight and blood sodium levels. Seizures were not associated with either dehydration or sodium concentration. Instead, they were predicted by higher distance speed and muscle cramps in the past.

The modern hypothesis explains the majority of such muscle cramps as a violation of neuromuscular control during fatigue: excitatory signals to the muscle prevail over inhibitory ones. That is why stretching the muscle, which activates the braking reflexes, often quickly relieves the cramp.

This is not to say that sodium never plays a role. For some "salty" athletes who sweat for hours in the heat, massive salt loss can be a factor. But as a universal explanation, the myth doesn't work, and "drinking more electrolytes" isn't a guaranteed way to get rid of a seizure.

Myth 2: isotonic protects against hyponatraemia

Many people think that hyponatraemia is only a risk for those who drink plain water, and a sports drink with sodium makes it safe to drink in any volume. This is a dangerous mistake.

Most sports drinks contain much less sodium than blood plasma. If a person drinks much more than he loses through sweat, the concentration of sodium in the blood still decreases. Research by Almond et al. (2005) in the Boston Marathon showed that weight gain during the race was the main risk factor, and beverage choice alone was not protective.

Hoffman and Stuempfle (2015) reached a similar conclusion in an ultramarathon: taking sodium supplements did not prevent hyponatraemia. The consensus of Hew-Butler et al. (2015) identify excessive drinking as a major cause of this condition and recommend drinking according to thirst.

So, electrolytes can be a useful part of a hydration strategy, but they don't override physics: the volume you drink must match the losses. Gaining weight during a marathon is a red flag, not a sign of good hydration.

Myth 3: "thirst is already too late"

The phrase that feeling thirsty means you are already severely dehydrated has been used in sports drink advertising and even in some coaching recommendations for years. She encouraged people to drink "in advance" on a strict schedule.

Thirst is a sensitive physiological mechanism that responds to small increases in plasma osmolality. In healthy people, during most loads, drinking when thirsty allows you to keep losses within safe limits. This is why the consensus on hyponatraemia recommends it as a basic strategy for prolonged events.

Timothy Noakes' book "Waterlogged" details how the idea of ​​constant preemptive drinking contributed to the spread of hyponatraemia among amateurs. Despite the debatability of individual theses of the author, the main idea — that thirst is a reliable reference point — is reflected in modern consensuses.

Exceptions exist: at very high intensity in the heat, when drinking is physically difficult, in elderly people with reduced thirst, and when you need to quickly recover between starts. Then a drinking plan based on weighing is more appropriate than intuition.

Myth 4: Everyone needs electrolytes every day

Marketing often suggests drinking electrolytes in the morning, at work, after coffee and before bed. However, for most people, the usual diet fully covers the need for sodium and chlorine, and often in excess. WHO advises adults to limit sodium to less than 2 g per day.

The need for additional sodium arises when sweat losses are significant: prolonged exercise, heat, physical work, several training sessions per day. The position statement of the American College of Sports Medicine (Sawka et al., 2007) links electrolyte recommendations to just such conditions.

As for potassium and magnesium, their deficiency does occur in the modern diet, but it is wiser to correct it with vegetables, fruits, legumes and nuts than with sports powders, where these minerals are usually low. Confirmed deficiency is treated by a doctor.

For a person who works out for an hour in the gym and works at a computer, daily electrolyte drinks are mostly excess sodium, sugar and waste. Water for thirst and normal nutrition do the same job.

Myths 5–6: clear urine and “natural” electrolytes

It is a common belief that a perfectly hydrated person has perfectly clear urine. In fact, persistently colourless urine often means that you are drinking more than you should. The NATA position (McDermott et al., 2017) considers urine colour as a rough guide, where a light yellow, straw colour corresponds to normal hydration.

In addition, the colour of urine depends on vitamins of group B, some products and medicines, and after a large volume of drinking, it quickly becomes lighter even when the tissues have not yet restored the balance. Therefore, it is more reliable for athletes to combine the colour of urine with weighing and the feeling of thirst.

Another popular myth is that coconut water, pink Himalayan salt, or “structured” mineral water are better, “natural” electrolytes. Coconut water is indeed high in potassium, but it's usually low in sodium, so it doesn't do a good job of making up for exactly what we lose through sweat.

Himalayan salt is mostly the same sodium chloride as common table salt, and traces of other minerals are negligible in terms of nutritional value. It has no proven benefits for hydration, although it is no more harmful than regular salt in the same amounts.

• Light straw-coloured urine is a normal reference point.
• Coconut water is a source of potassium, but not sodium.
• "Pink" salt does not give advantages over regular for hydration.
• Milk and broth are underrated “natural” recovery drinks.

Editorial conclusions

Most myths about electrolytes grow from a true kernel—we do lose sodium through sweat—which is then inflated into universal rules. Reality is more complex and individual.

Cramps are mostly not associated with salt deficiency, isotonic does not protect against hyponatraemia with excessive drinking, and thirst is a more reliable guide than advertised. For most people, daily electrolyte supplements are unnecessary.

Electrolytes make sense in specific situations: long and hot loads, "salty" sweat, rapid recovery after weight loss. That's where they work best.

To learn more, read our articles "The Benefits of Electrolytes for Athletes: The Evidence Base," "How to Take Electrolytes: Dosage, Timing, Duration," and "Who Should Not Take Electrolytes."

List of used literature

1. Schwellnus MP, Drew N, Collins M. Increased running speed and previous cramps rather than dehydration or serum sodium changes predict exercise-associated muscle cramping: a prospective cohort study in 196 Ironman triathletes. Br J Sports Med. 2011;45(8):650–656.
2. Almond CSD, Shin AY, Fortescue EB, et al. Hyponatremia among runners in the Boston Marathon. N Engl J Med. 2005;352(15):1550–1556.
3. Hoffman MD, Stuempfle KJ. Sodium supplementation and exercise-associated hyponatremia during prolonged exercise. Med Sci Sports Exerc. 2015;47(9):1781–1787.
4. Hew-Butler T, Rosner MH, Fowkes-Godek S, et al. Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Clin J Sport Med. 2015;25(4):303–320.
5. Noakes T. Waterlogged: The Serious Problem of Overhydration in Endurance Sports. Champaign, IL: Human Kinetics; 2012.
6. Sawka MN, Burke LM, Eichner ER, et al. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc. 2007;39(2):377–390.
7. McDermott BP, Anderson SA, Armstrong LE, et al. National Athletic Trainers' Association position statement: fluid replacement for the physically active. J Athl Train. 2017;52(9):877–895.
8. World Health Organization. Guideline: Sodium intake for adults and children. Geneva: WHO; 2012.