A Nutritionists Guide To Electrolytes

Everywhere you go on the internet at the moment there are ads for this supplement or that tablet which will help you improve your performance. Electrolytes is one of those supplements that gets near constant attention on social media with many people describing it as the key pillar to performance. But what are they? Why do we need them? And should athlete be adding it to their nutritional intake?

We asked our in house expert nutritionist Ella Myers to give us the lowdown on the do's and don't of electrolytes!

What are electrolytes?

An electrolyte is a mineral that has an electrical charge when dissolved in water,

such as sodium (Na + ), Potassium (K + ), Chloride (Cl - ), Magnesium (Mg 2+ ), or Calcium

(Ca 2+ ). These all come from food/ fluids and are essential for multiple bodily

functions, including the production of energy, nerve signalling for muscular

contraction, and fluid balance for the maintenance of blood pressure.

To supplement or not to supplement…

Sweating is a key cooling mechanism during exercise, allowing the evaporation of

heat, but also the loss of fluid and small quantities of electrolytes. Your sweat rate

can vary significantly from person to person and day-to-day, due to variables such as

body weight, environmental temperature, clothing, or exercise intensity. Therefore,

the need for electrolyte supplementation depends on these factors.

Sodium and chloride are the two electrolytes found in the highest quantities in sweat;

however, the concentrations of these electrolytes within the body are tightly

regulated, and adaptations in the kidneys and sweat glands can take place to

minimise losses if required. Therefore, scientific evidence and guidelines from

leading bodies such as the American College of Sports Medicine only support the

replacement of one particular electrolyte, sodium, during endurance exercise lasting

over 2 hours. The general guideline is to consume 300-600mg of sodium per hour during

exercise of these durations. But it is a good idea to check your energy gels/bars, as it

is likely that these contain some sodium anyway.

After exercise, the goal is to replace any fluid or electrolytes lost. Providing you have

sufficient recovery time between sessions (over 12 hours), consuming normal meals and

snacks with appropriate water intake should be adequate as many foods can supply

the required electrolytes. When quick rehydration is necessary – such as after very

prolonged exercise, training in hot conditions, or when recovery time between

sessions is limited – electrolyte supplementation can play a key role in balancing

fluid intake and losses and maintaining an appropriate blood osmolarity (the

concentration of solutes in the blood). Electrolyte-containing drinks (e.g., sports

beverages or hydration tablets dissolved in water) may be helpful in these scenarios.

The bottom line

Electrolyte supplementation isn’t always as necessary as you may think. Research

only supports the consumption of additional sodium (300-600mg/h) during exercise

over 2 hours. As the modern diet is abundant in electrolytes, particularly sodium, unless rapid

recovery is required or large fluid losses (hypo-hydration) are experienced, both fluid

and electrolyte losses from sweat can be replaced by normal eating and drinking.

This blog was written by Ella Myers who holds a BSc in Nutrition Exercise and Health and is currently finishing her Masters in Applied Sports Nutrition. Having won numerous academic awards during her undergraduate degree Ella has also had her research published. Ella balance her studies alongside working with athletes from and through PGC1-Coaching as well as athletes at the St Mary's University Elite Training Centre. Ella is available to work with you directly on your nutrition and help you take the next steps in your performance. You can find out about her service offering using the link here.

Further Reading and Guidelines

American College of Sports Medicine, Sawka, M. N., Burke, L. M., Eichner, E. R.,

Maughan, R. J., Montain, S. J., & Stachenfeld, N. S. (2007). American College of

Sports Medicine position stand. Exercise and fluid replacement. Medicine and

Science in Sports and Exercise, 39(2), 377–390.

https://doi.org/10.1249/mss.0b013e31802ca597

Kerksick, C. M., Wilborn, C. D., Roberts, M. D., Smith-Ryan, A., Kleiner, S. M., Jäger,

R., Collins, R., Cooke, M., Davis, J. N., Galvan, E., Greenwood, M., Lowery, L. M.,

Wildman, R., Antonio, J., & Kreider, R. B. (2018). ISSN exercise & sports nutrition

review update: research & recommendations. Journal of the International Society of

Sports Nutrition, 15(1), 38. https://doi.org/10.1186/s12970-018-0242-y

Shirreffs, S. M., & Sawka, M. N. (2011). Fluid and electrolyte needs for training,

competition, and recovery. Journal of Sports Sciences, 29 Suppl 1, S39–S46.

https://doi.org/10.1080/02640414.2011.614269

Veniamakis, E., Kaplanis, G., Voulgaris, P., & Nikolaidis, P. T. (2022). Effects of

Sodium Intake on Health and Performance in Endurance and Ultra-Endurance

Sports. International Journal of Environmental Research and Public Health, 19(6),

3651. https://doi.org/10.3390/ijerph19063651