Do Athletes Need Added Electrolytes?

If dietary guidelines recommend limiting salt, why, and when might mineral salt supplementation be warranted?

The major reason is that public health sodium guidelines (e.g., <2,300 mg/day in the U.S.) are designed to reduce hypertension and cardiovascular disease risk in the general population. Unfortunately, these days a lot of the general population is largely sedentary and chronically overconsuming sodium from processed foods. As a result, they may have hypertension and subsequently would benefit from a lower sodium diet to help combat excess sodium intake and the corresponding hypertension. It is important to note that the guidelines of “limiting salt intake” are not necessarily intended for individuals experiencing large, acute sodium losses, such as athletes, military personnel, or individuals exposed to heat stress (manual laborers, landscapers, etc.).

There are certain circumstances where supplemental sodium may be warranted and could be helpful (pending on other dietary habits/intake). These may include prolonged endurance exercise (generally lasting >90 minutes), high sweat rates (>1.5–2.0 L/h, which are likely in hot and humid environments), repeated daily training sessions (again, more so in hot/humid environments), and individuals with high sweat sodium concentrations (“salty sweaters”). The primarily underlying reason or mechanism why more sodium could be helpful is because from a physiological standpoint, sodium is the primary extracellular ion (electrolyte) and is essential for maintenance of plasma volume. Sodium is also involved with nerve impulse transmission, muscle contraction, and glucose/fluid absorption via sodium-glucose cotransporters. Because of this, sodium restriction (or inadequate sodium intake) may impair thermoregulation, cardiovascular function, and performance. Also, from a rehydration standpoint, restricting sodium could increase the risk of exercise-associated hyponatremia, specifically if fluid intake (plain water only) is high but sodium intake is inadequate.

How much salt is lost in sweat, and why consume salt if blood sodium rises after exercise?

The amount of sodium lost via sweat varies widely based on the person. It can range from ~20–80 mmol/L sodium (or ≈460–1,840 mg of sodium per liter of sweat). The amount of sweat a person loses during exercise or heat exposure also varies widely with typical sweat rates ranging from 0.5–2.5 L/h. As a result, total sodium losses can exceed 3–5 grams of salt during prolonged or intense exercise in hot/humid conditions or in a person working outdoors (i.e., landscaper) during the summer months. In addition to sodium loss, potassium, calcium, and magnesium are other electrolytes that can also be lost via sweat, just in in much smaller amounts and are generally replaced adequately through diet.

Why does blood sodium sometimes increase after exercise?

This is where things start to get confusing a bit. The statement that “sweating increases blood sodium levels” is conditionally correct, but it is reflecting hemoconcentration (aka the CONCENTRATION of sodium in the blood), not total sodium amounts. Sweat is hypotonic relative to plasma, which is one of the reasons why more water than sodium is lost via sweat. And as a result, plasma volume decreases, which in turn means that serum sodium concentration transiently increases. However, this does not mean the body has excess sodium, as total body sodium is still reduced. And importantly, if rehydration occurs with plain water only, plasma sodium can continue to decline, increasing hyponatremia risk.

So, to combat this, consuming sodium post-exercise can help restore total body sodium, supports plasma volume recovery, enhance fluid retention by reducing urine output, and subsequently stimulate thirst (which also improves rehydration).

Do electrolytes enhance performance, recovery, or prevent muscle cramps?

This is a tricky question to answer as well. I don’t think electrolytes would necessarily enhance performance on their own, but they could help maintain performance or minimize declines in performance during prolonged bouts of physical activity (i.e., during a Triathlon). For example, from a mechanism standpoint, electrolytes may indirectly support performance by helping to maintain plasma volume, which could help maintain stroke volume and cardiac output during exercises and mitigate increases in heart rate (thereby helping to attenuate increases in cardiovascular strain during activity, especially in hot/humid environments). Electrolytes could also help by facilitating carbohydrate and fluid absorption in the gut via sodium-glucose transporters. Research has shown that sodium ingestion during prolonged exercise improves endurance capacity, particularly when fluid losses are high or exercise duration is long, primarily via hydration and thermoregulatory mechanisms rather than direct ergogenic effects.

In terms of recovery, sodium-containing fluid can help improve post-exercise fluid retention and accelerate the restoration of plasma volume. This could be helpful to enhance subsequent exercise capacity when sessions are closely spaced or for a weight-class athlete who may have restricted fluids/sodium to “cut weight” and then would need to recover (rehydrate) quickly before competing. Research has shown that sports drinks help wrestlers recover more quickly after making weight when compared to plain water.

In terms of muscle cramps, contrary to popular belief, electrolyte depletion alone is not the primary cause of exercise-associated muscle cramps. Current evidence supports a neuromuscular fatigue model, rather than sodium loss alone. Although sodium depletion may contribute in some cases, particularly during heavy sweat loss. As a result, electrolytes are not a guaranteed cramp preventative, but may help individuals with high sweat sodium losses and a history of cramping during prolonged exercise

Are electrolytes useful beyond sport (e.g., illness, dehydration, hangovers)?

Yes, electrolytes have benefits for other situations and populations beyond athletics. For example, during certain illnesses (vomiting, diarrhea), oral rehydration solutions (ORS) containing sodium and glucose will be extremely helpful to maximize the utility of sodium-glucose cotransporters to maximize fluid absorption.

Also, alcohol-related dehydration (aka hangovers) are partially a result of alcohol increasing diuresis and sodium loss. Electrolyte-containing fluids may therefore help improve rehydration efficiency and reduce symptoms related to hypovolemia in individuals who are suffering from hangovers. However, they do not counteract alcohol’s toxic effects.

Are branded electrolyte products superior to salt + water?

From a biochemical perspective, sodium is the critical component. However, branded products may offer advantages and potential benefits such as more precise sodium dosing and the inclusion of glucose to enhance absorption. Additionally, several of them will have improved palatability, helping with greater voluntary intake and being conducive for overall convenience and consistency of intake.

However, not all of them are perfect as many products may actually be underdosed in sodium or other electrolytes. Also, several of them would probably be considered unnecessary for low-intensity or short-duration exercise. As a result, the cost of some of them probably far exceeds that of the raw ingredients alone. Table salt + water alone could be considered an option if appropriately dosed, but most individuals underestimate required sodium concentrations.

Are electrolytes a “scam,” or do they provide real benefits?

Similar to some of the answers above, I don’t think electrolytes are neither a scam nor universally necessary for everyone. If we consider the cumulative evidence, electrolytes could be considered unnecessary for sedentary individuals or short, low-intensity exercise (assuming somewhat healthy/well-balanced dietary intake). But they would likely be beneficial during prolonged, intense, or heat-stress conditions. Additionally, they would be considered clinically essential during dehydration from illness.

So, for athletes, laborers, and tactical personnel (e.g., military or firefighters) their recommended use would be considered context-dependent, and not inherently ergogenic. Claims that electrolytes are always useless oversimplifies the science, just as claims that everyone needs them kind of exaggerates the benefits. I would say that the scientific consensus supports targeted use based on sweat loss, exercise duration, environment, and individual variability, or as indicated during periods of illness.

So, would a sedentary person, who eats a diet high in processed foods and sits inside in the AC all day need to consumed electrolyte packets? No.

Would an endurance athlete training in Austin, TX benefit from adding electrolyte packets to their daily regimen benefit? Yes, absolutely (And I think James would agree as well).

I think that electrolytes are best understood as physiological tools, and not performance hacks. Their value depends on context, dose, and need. If used appropriately, they can support hydration, cardiovascular function, and recovery. However, used indiscriminately, they offer little benefit beyond flavored water and if anything may do more harm than good (e.g., a sedentary person with high blood sugar loading up on electrolyte packets because they think they are “healthy”) and could be considered a waste of money if purchasing expensive commercial brands.

References:

1. Standing Committee on the Scientific Evaluation of Dietary Reference Intakes, Panel on Dietary Reference Intakes for Electrolytes, & Water. (2005). Dietary reference intakes for water, potassium, sodium, chloride, and sulfate. National Academies Press.
   1. Maughan, R. J., & Shirreffs, S. M. (2010). Dehydration and rehydration in competitive sport. Scandinavian journal of medicine & science in sports, 20, 40-47. https://doi.org/10.1111/j.1600-0838.2010.01207 
   1. McDermott, B. P., Anderson, S. A., Armstrong, L. E., Casa, D. J., Cheuvront, S. N., Cooper, L., … & Roberts, W. O. (2017). National athletic trainers’ association position statement: fluid replacement for the physically active. Journal of athletic training, 52(9), 877-895.
   1. Stand, A. P. (2009). Exercise and fluid replacement. Medicine and science in sports and exercise, 39(2), 377-390.
   1. Burke, L. M., & Hawley, J. A. (2018). Swifter, higher, stronger: what’s on the menu?. Science, 362(6416), 781-787.
   1. Shirreffs, S. M., & Sawka, M. N. (2011). Fluid and electrolyte needs for training, competition, and recovery. Journal of sports sciences, 29(sup1), S39-S46. https://doi.org/10.1080/02640414.2011.614269
   1. Thomas, D. T., Erdman, K. A., & Burke, L. M. (2016). Nutrition and athletic performance. Med Sci Sports Exerc, 48(3), 543-568. https://10.1249/MSS.0000000000000852
   1. Maughan, R. J., & Shirreffs, S. M. (2010). Development of hydration strategies to optimize performance for athletes in high‐intensity sports and in sports with repeated intense efforts. Scandinavian journal of medicine & science in sports, 20, 59-69. https://doi.org/10.1111/j.1600-0838.2010.01191
   1. Maughan, R. J. (2009). Sports beverages for optimising physical performance. In Functional and speciality beverage technology (pp. 346-369). Woodhead Publishing. https://doi.org/10.1533/9781845695569.3.346
   1. Merson, S. J., Maughan, R. J., & Shirreffs, S. M. (2008). Rehydration with drinks differing in sodium concentration and recovery from moderate exercise-induced hypohydration in man. European Journal of Applied Physiology, 103(5), 585-594. https://doi.org/10.1007/s00421-008-0748-0
   1. Miller, K. C., McDermott, B. P., Yeargin, S. W., Fiol, A., & Schwellnus, M. P. (2022). An evidence-based review of the pathophysiology, treatment, and prevention of exercise-associated muscle cramps. Journal of athletic training, 57(1), 5-15. https://doi.org/10.4085/1062-6050-0696.20
   1. Maughan, R. J., & Shirreffs, S. M. (2019). Muscle cramping during exercise: causes, solutions, and questions remaining. Sports Medicine, 49(2), 115-124. https://doi.org/10.1007/s40279-019-01162-1
   1. World Health Organization. (2006). Oral rehydration salts: Production of the new ORS (No. WHO/FCH/CAH/06.1). World Health Organization.
   1. Shirreffs, S. M., & Maughan, R. J. (1997). Restoration of fluid balance after exercise-induced dehydration: effects of alcohol consumption. Journal of Applied Physiology, 83(4), 1152-1158. https://doi.org/10.1152/jappl.1997.83.4.1152
   1. Evans, G. H., James, L. J., Shirreffs, S. M., & Maughan, R. J. (2017). Optimizing the restoration and maintenance of fluid balance after exercise-induced dehydration. Journal of Applied Physiology. https://doi.org/10.1152/japplphysiol.00745.2016
   1. Clarke, M. M., Stanhewicz, A. E., Wolf, S. T., Cheuvront, S. N., Kenefick, R. W., & Kenney, W. L. (2019). A randomized trial to assess beverage hydration index in healthy older adults. The American journal of clinical nutrition, 109(6), 1640. https://doi.org/10.1093/ajcn/nqz009
   1. Baker, L. B., Barnes, K. A., Anderson, M. L., Passe, D. H., & Stofan, J. R. (2016). Normative data for regional sweat sodium concentration and whole-body sweating rate in athletes. Journal of sports sciences, 34(4), 358-368. https://doi.org/10.1080/02640414.2015.1055291
   1. Hew-Butler, T., Rosner, M. H., Fowkes-Godek, S., Dugas, J. P., Hoffman, M. D., Lewis, D. P., … & Verbalis, J. G. (2015). Statement of the third international exercise-associated hyponatremia consensus development conference, Carlsbad, California, 2015. Clinical Journal of Sport Medicine, 25(4), 303-320. https://doi.org/10.1097/JSM.0000000000000221
   1. Valiente, J. S., Utter, A. C., Quindry, J. C., & Nieman, D. C. (2009). Effects of commercially formulated water on the hydration status of dehydrated collegiate wrestlers. The Journal of Strength & Conditioning Research, 23(8), 2210-2216. https://doi.org/10.1519/JSC.0b013e3181bac56e