Some Athletes May Need Salt Supplementation During Endurance Events Interview with:
Juan Del Coso Garrigós
Profesor CC. de la Act. Física y del Deporte
Responsable del Laboratorio de Fisiología del Ejercicio

MedicalResearch: What is the background for this study? What are the main findings?

Response: From a scientific point of view, it is well known that salt (either in capsules or included in a drink) can improve physical performance and several other physiological factors such as plasma volume maintenance, thermoregulation, etc in endurance activities.  These effects are more evident when the amount of salt ingested during exercise matches the amount of salt lost by sweating.  By using only sports drinks, it is impossible to replace all the salt lost by sweating because they only contain a relatively small amount of salt in their compositions (between ½ and 1/3 of the amount of salt lost by sweating).

In fact, some of the investigations that determined the effectiveness of ingesting salt in sports have been financed by most popular sport drinks trademarks.  However, sports drink companies only include a part of the salt lost by sweating because for them, taste is elemental for their markets!  I suppose that, if they include more salt in their commercially available drinks, they would be more effective to prevent dehydration and performance decline, but at the same time, the taste of the drink would diminish the amount of beverage ingested worldwide.

In this case, in the sport drinks market there is a well- established balance between taste and physiological effectiveness.

As an example, most “salted” sport drinks contain 20-25 mM of sodium while it is well known that sweat sodium concentration ranges from 20 to 60 mM (salty sweater can reach 100 mM!!).  This is not a regulatory limitation, because UE considers sports drinks to carbohydrate-electrolyte solutions that contain sodium between 20 and 50 mM.

Our main finding is: To ingest salt capsules, in addition to the habitual rehydration routines with sports drinks, improves performance in a triathlon.  This ergogenic effect was mediated by better maintenance of body water and electrolytes balances.

MedicalResearch: What should clinicians and patients take away from your report?

Response: The results of our investigation are only applicable to athletes and especially to endurance athletes involved in long-distance/long-lasting competitions. For these athletes, the take home message is “matching (or trying to match) sweat electrolyte losses to salt ingestion” might be an easy and effective strategy to improve performance and to avoid electrolyte imbalances such as hyponatremia.

In this case, it would be incorrect to recommend “an amount of salt for athletes” because the salt lost during exercise varies from disciplines (marathon vs gymnastics, for example, would have very different demands of sodium), environmental conditions, genetics, etc.

It is also important to remark that the outcomes of this investigation are not applicable to healthy and/or inactive people. They do not need “extra” salt because they do not loss it (the amount of sweat produced during a regular day without exercise or sport activities is very low and the salt lost by urine can be easily recovered with the diet).

MedicalResearch: What recommendations do you have for future research as a result of this study?

Response: In the future, investigations should focus on the design of devices that (easily) measure electrolyte concentrations in thermoregulatory sweat, the determination of factors that influence the sweat electrolyte concentrations, efficacy of sport drinks with higher amounts of salt (in comparison to present compositions), etc.


Del Coso, C. González-Millán, J. J. Salinero, J. Abián-Vicén, F. Areces, M. Lledó, B. Lara, C. Gallo-Salazar, D. Ruiz-Vicente. Effects of oral salt supplementation on physical performance during a half-ironman: A randomized controlled trial. Scandinavian Journal of Medicine & Science in Sports, 2015; DOI: 10.1111/sms.12427 Interview with:  Juan Del Coso Garrigós (2015). Some Athletes May Need Salt Supplementation During Endurance Events