Updated: Nov 17
When we exercise, we lose electrolytes in our sweat. But does this mean we need to take electrolyte supplements?
As you’ll know, when you work out hard—be that on the pitch, on the road, in the gym, or elsewhere—you will sweat quite a bit. While the amount of sweat produced will vary from person to person (Figure 1) and from sport to sport, most people will lose a considerable amount of sodium—or salt—as a result of this (as sodium is a component of sweat) (1). Because sodium is important for hydration, we need to replace it to properly rehydrate. Ergo, that’s where the rationale for taking electrolytes comes in.
Figure 1. Sweating rate of athletes from various different sports. As you can see, some people sweat close to zero litres per hour (L/h), while others sweat more than three L/h (1).
Electrolytes are minerals that carry an electrical charge when dissolved in water. Examples include sodium, potassium, calcium, and magnesium. When it comes to hydration, the most important electrolyte is sodium. This is because: 1) we lose a lot of sodium through sweat; and 2) sodium helps us to absorb and retain the water that we drink (2).
The performance implications of replenishing this lost sodium (and fluids) are super important. Moderate dehydration (i.e., a reduction in body weight of ~3–4% due to sweat losses) appears to decrease strength by ~2%, power by ~3%, and high-intensity endurance performance by ~10% (3). It goes without saying that, if at all possible, we would like to avoid this through proper hydration.
Naturally, electrolyte supplements are usually rich in sodium and lower in other electrolytes. This makes sense because we lose about 10 times more sodium than other electrolytes (e.g., potassium) through sweat (4). In a similar vein, sports drinks like Lucozade Sport contain more sodium than other electrolytes. But is it really necessary to buy electrolyte supplements for optimal hydration?
Visit our article on sports drinks to see whether they’re worth taking.
Should You Take Electrolytes?
The answer is: probably not. Unless you’re a marathon runner or ultra-endurance athlete—where you’re at risk of drinking too much water and therefore consuming too little sodium relative to fluids—taking electrolytes is likely unnecessary. In fact, just drinking plain water and eating a meal after training is enough to ensure proper rehydration for most people, and this is echoed by the UEFA expert group on nutrition in elite football (5). If you have had a particularly strenuous session or match, adding a pinch of salt to this meal will do the trick.
Taking electrolyte supplements when you don’t need to can actually be unwise for heart health. This is because excess sodium (or salt) intake increases blood pressure, which increases our risk for heart disease (6). So keep this in mind when deciding whether or not to take electrolytes.
Unless you’re running marathons, or exercising at a high intensity for multiple hours at a time, electrolyte supplements are probably not doing you any favours. Save your money and drink plain water with some food after exercise. And add a pinch of salt to your meal if you sweated a considerable amount during your session.
If you would like supplemental football training to improve your skills, reach out to our team of expert coaches at [email protected] to get started. And if you enjoyed this article, sign up to our mailing list to stay up to date.
Thank you for reading and have a great weekend!
Patrick Elliott, BSc, MPH
Health and Nutrition Science Communication Officer at Training121
(1) Barnes KA, Anderson ML, Stofan JR, et al. Normative data for sweating rate, sweat sodium concentration, and sweat sodium loss in athletes: An update and analysis by sport. J Sports Sci. 2019;37(20):2356–66. Available at: https://www.tandfonline.com/doi/full/10.1080/02640414.2019.1633159
(2) Shirreffs SM. Hydration in sport and exercise: water, sports drinks and other drinks. Nutr Bull. 2009;34(4):374–9. Available at: https://onlinelibrary.wiley.com/doi/10.1111/j.1467-3010.2009.01790.x
(3) Judelson DA, Maresh CM, Anderson JM, et al. Hydration and muscular performance: does fluid balance affect strength, power and high-intensity endurance?. Sports Med. 2007;37(10):907–21. Available at: https://link.springer.com/article/10.2165/00007256-200737100-00006
(4) Shirreffs SM, Armstrong LE, Cheuvront SN. Fluid and electrolyte needs for preparation and recovery from training and competition. J Sports Sci. 2004;22(1):57–63. Available at: https://pubmed.ncbi.nlm.nih.gov/14971433/
(5) Collins J, Maughan RJ, Gleeson M, et al. UEFA expert group statement on nutrition in elite football. Current evidence to inform practical recommendations and guide future research. Br J Sports Med. 2021;55(8):416. Available at: https://bjsm.bmj.com/content/55/8/416.long
(6) Stamler J. The INTERSALT Study: background, methods, findings, and implications. Am J Clin Nutr. 1997;65(2 Suppl):626S–42S. Available at: https://pubmed.ncbi.nlm.nih.gov/9022559/
Electrolytes: Minerals that carry an electrical charge when dissolved in water, e.g., sodium and potassium. When we sweat, we lose electrolytes, and must replace them via fluids or food. Electrolyte (sodium) losses are not of huge concern in lower intensity exercise, but become more important the longer and more intense the exercise, and especially in hot conditions.