What Are Electrolytes? (Do You Need To Supplement?)

April 7, 2024

You show up to training every day. You train hard, nail your protein goals, and have a progressive training program to help you gain strength. Yet, amidst all the focus on your training program, macronutrients, and food intake, the importance of fluids and electrolytes often takes a backseat. But what are electrolytes, and why are they important in hydration and performance?

Electrolytes are sodium, potassium, chloride, calcium, magnesium, and phosphate, which form electrical charges with specific functions. They are essential for hydration because they help regulate the balance of fluids in our bodies. When we sweat or lose fluids, we also lose electrolytes like sodium, potassium, and chloride. Without enough electrolytes, our bodies may struggle to retain water effectively, leading to dehydration.

Let’s unpack some of the science behind electrolytes, how they work, and why they matter to you as an athlete.

What Are Electrolytes?

As mentioned, electrolytes get their name because they form ions in water, producing an electrical charge. They fall into three categories: acids, bases, and salts [1]. They include:

  • Sodium
  • Potassium
  • Chloride
  • Calcium
  • Magnesium and
  • Phosphate.

These minerals are dissolved in bodily fluids like blood, urine, and sweat, and they help regulate important processes such as balancing fluids, transmitting nerve signals, contracting muscles, and maintaining the body’s pH levels.

We get electrolytes from the foods and drinks we take in, and it’s crucial to maintain the right balance of electrolytes for overall health and proper bodily function [2].

Do You Need To Take Electrolytes?

Do You Need Electrolytes

As with all things nutrition, the answer to this is: it depends. If you are not training, you probably do not need to take in extra electrolytes. However, once you start exercising, your need for electrolytes changes according to your training load.

Hard workouts and hot weather make you sweat, causing you to lose water and essential minerals called electrolytes.

During hot weather, active people can lose between 4 to 10 liters of water and 3500 to 7000 milligrams of sodium [3] per day (of course, this depends on how long and hard you are training)

This loss can create a shortage of water and electrolytes in the body. To get back to a normal level of hydration, called “euhydration,” and perform well, it’s important to replenish these fluids and minerals promptly [3].

In a consensus statement from the American College of Sports Medicine roundtable on hydration and physical activity, it was concluded that, after exercising, it’s crucial to replace all the fluids and electrolytes you lost [4].

This means drinking fluids with electrolytes, like glucose-electrolyte solutions (think Powerade, Gatorade, etc), instead of just water.

What Happens If Your Body Is Low On Electrolytes?

When your body lacks electrolytes, it can negatively affect your body and performance. Severe electrolyte imbalances can be dangerous and may need urgent medical attention. These can include [5, 6, 7, 8]:

  1. Muscle cramps or weakness: While cramping is a multi-factorial problem, low levels of electrolytes like potassium, calcium, and magnesium could contribute to muscle cramps, weakness, or spasms.
  1. Fatigue or lethargy: Electrolytes help regulate nerve impulses and energy production, so low levels may result in feelings of fatigue or weakness.
  1. Irregular heartbeat: Proper levels of electrolytes such as potassium and calcium are essential for maintaining a normal heart rhythm. When they’re low, it can cause irregular heartbeats.
  1. Dizziness or lightheadedness: Electrolyte imbalances can affect blood pressure and fluid balance, leading to dizziness or feeling lightheaded, especially when standing up quickly.
  1. Nausea or vomiting: Changes in electrolyte levels can impact digestion, leading to symptoms like nausea, vomiting, or diarrhea.
  1. Headaches: Electrolyte changes, particularly in sodium levels, can contribute to headaches or migraines.
  1. Confusion or difficulty concentrating: Electrolyte imbalances might affect brain function, causing confusion, difficulty concentrating, or changes in mental state.

Important: While the lack of electrolytes can cause these symptoms, it is also important to remember that taking too much can also be a problem. For example, taking too much sodium can cause a condition called hypernatremia [9] (too much sodium in the blood). This can cause symptoms similar to dehydration.

Good hydration is a delicate balance between fluid and electrolyte intake.

Which Electrolytes Are Most Important During Exercise?

How Much Electrolytes To Take

During exercise, some electrolytes are especially important to maintain performance and health:

  1. Sodium [10]:Sodium helps maintain fluid balance and plays a key role in nerve function and muscle contraction. During exercise, sodium is lost through sweat, and it’s important to replace it to prevent dehydration and maintain proper muscle function.
  1. Potassium [11]: Potassium is important for muscle contraction, nerve function, and maintaining fluid balance. It works alongside sodium to regulate muscle contractions during exercise. Low potassium levels can lead to muscle weakness, cramps, and irregular heartbeats.
  1. Chloride [10, 11]: Chloride works with sodium to maintain fluid balance and is involved in the production of stomach acid, aiding digestion (remember good ol’ table salt that you usually use on your food? That is a combination of sodium and chloride). During exercise, chloride may be lost through sweat.
  1. Calcium [12]: Many athletes see calcium as a mineral crucial for bone health—but that is not all that it is good for! Calcium is essential for muscle contraction, including the contraction of the heart muscle. It also plays a role in nerve transmission and bone health. While calcium loss during exercise is minimal compared to other electrolytes, maintaining adequate levels is still important for overall muscle and nerve function.
  1. Magnesium [13]: Magnesium is involved in over 300 biochemical reactions in the body, including energy metabolism, muscle and nerve function, and protein synthesis.
  1. Phosphate [14]: Phosphate is involved in energy metabolism, particularly in the production of ATP (the energy currency of your cells). While phosphate loss during exercise is relatively low, it still contributes to maintaining proper energy levels and muscle function.

How Much Electrolytes Do I Need?

While each athlete is different, and sweat rates can depend on the temperature, humidity, and intensity of the training session/race, some guidelines exist for the amount of electrolytes you need on a given day.


The American College of Sports Medicine (ACSM) recommends consuming about 300–600 mg of sodium per hour or 1.7–2.9 g of salt during a longer training session (> 60 min) [15].


The potassium concentration lost in sweat varies depending on factors such as heat exposure and physical activity.

Studies have shown that potassium losses from sweat can range from 90 to 626 mg/L (2 to 16 mmol/L) when sweat losses are minimal [16].

However, during longer activities, such as 6 hours of intermittent treadmill activity in 40°C (104°F) heat, potassium losses from sweat can be up to approximately 1,200 mg/d to 2,300 mg/d [17].

In addition to this, you also need potassium for daily activities.

Although there are no specific recommendations for potassium intake for athletes, based on the RDA (Recommended Daily Amount) and the sweat losses of athletes, it is safe to say that you can aim for about 2700 – 4700 mg per day if you are a healthy athlete with no conditions like kidney disease.


Athletes lose 5.98 grams to 14.03 grams of chloride daily [18]. However, you get extra chloride when you eat salty foods like crackers, pretzels, soups, stews, etc.


Adult athletes need about 1200mg of calcium daily, whereas female athletes with low bone density or amenorrhoea (lack of a period) need about 1800 mg per day [19].


Women and men between 19 – 30 years need 310 mg and 400 mg of magnesium per day, respectively. This increases to 320 – 420 mg per day for women and men between the ages of 31 – 50 years [20].


For adults, including pregnant and lactating women, the RDA for phosphorus is 700 mg per day, although most adults consume much more than this every day [21].

How To Choose An Electrolyte Supplement

When you look at a sports drink or gel product, try to see it in order of priority (per 100 ml in a sports drink or gel). This is a glucose-electrolyte drink and can help you be energized and stay hydrated.

  1. First, ensure that there is 120 – 220g of sodium
  2. Then, if possible, 80 – 100 mg potassium
  3. Often, magnesium is a nice “cherry on top”—about 20 – 60 mg would be quite sufficient.


Regardless of the level of sports you play, fluids and electrolytes are cornerstones of your athletic performance.

Electrolytes support hydration, muscle function, and overall well-being. By prioritizing strategic fluid and electrolyte replacement practices, you can optimize your performance, enhance recovery, and mitigate the risk of dehydration and electrolyte imbalance.


  1. Juilus et al. (1953). Electrolytes. *Postgraduate Medical Journal, 29*(1), 1-1. https://doi.org/10.1007/978-3-662-46875-3_100794
  2. Boulay, M. R., Serresse, O., Thériault, G., Simoneau, J. A., Bouchard, C., & Song, T. M. (1995). Changes in plasma electrolytes and muscle substrates during short-term maximal exercise in humans. *Canadian Journal of Applied Physiology, 20*(1), 89-101.
  3. 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
  4. Casa, D. J., Clarkson, P. M., & Roberts, W. O. (2005). American College of Sports Medicine roundtable on hydration and physical activity: consensus statements. *Current Sports Medicine Reports, 4*(3), 115–127. https://doi.org/10.1097/01.CSMR.0000306194.67241.76
  5. Rosner, M. H., & Kirven, J. (2007). Exercise-associated hyponatremia. *Clinical Journal of the American Society of Nephrology, 2*(1), 151-161.
  6. Holmes, N., Bates, G., Zhao, Y., Sherriff, J., & Miller, V. (2016). The effect of exercise intensity on sweat rate and sweat sodium and potassium losses in trained endurance athletes. *Annals of Sports Medicine and Research, 3*(2), 1-4.
  7. Laires, M. J., Monteiro, C. P., Matias, C. N., Santos, D. A., Silva, A. M., & Bicho, M. (2014). Magnesium status and exercise performance in athletes. *Trace Elements & Electrolytes, 31*(1).
  8. Yusni, Y. (Year). Long-term effect of moderate to high-intensity exercise on blood pressure and calcium in young athletes: A retrospective study. In *The 7th AIC-ICMR on* (pp. 356).
  9. Krabak, B. J., Lipman, G. S., Waite, B. L., & Rundell, S. D. (2017). Exercise-associated hyponatremia, hypernatremia, and hydration status in multistage ultramarathons. *Wilderness & Environmental Medicine, 28*(4), 291-298.
  10. Pourvaghar, M. J., & Soori, R. (2007). A survey of sodium and potassium alterations during rest time after aerobic activities in athletes. *Australian Journal of Basic and Applied Sciences, 1*(4), 687-690.
  11. Holmes, N., Bates, G., Zhao, Y., Sherriff, J., & Miller, V. (2016). The effect of exercise intensity on sweat rate and sweat sodium and potassium losses in trained endurance athletes. *Annals of Sports Medicine and Research, 3*(2), 1-4.
  12. Kunstel, K. (2005). Calcium requirements for the athlete. *Current Sports Medicine Reports, 4*(4), 203-206.
  13. Nica, A. S., Caramoci, A., Vasilescu, M., Ionescu, A. M., Paduraru, D., & Mazilu, V. (2015). Magnesium supplementation in top athletes-effects and recommendations. *Sports Medicine Journal/Medicina Sportivâ, 11*(1).
  14. Kopec, B. J., Dawson, B. T., Buck, C., & Wallman, K. E. (2016). Effects of sodium phosphate and caffeine ingestion on repeated-sprint ability in male athletes. *Journal of Science and Medicine in Sport, 19*(3), 272-276.
  15. 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
  16. Consolazio, C. F., Matoush, L. O., Nelson, R. A., Harding, R. S., & Canham, J. E. (1963). Excretion of sodium, potassium, magnesium and iron in human sweat and the relation of each to balance and requirements. *Journal of Nutrition, 79*, 407–415.
  17. Armstrong, L. E., Hubbard, R. W., Szlyk, P. C., Matthew, W. T., & Sils, I. V. (1985). Voluntary dehydration and electrolyte losses during prolonged exercise in the heat. *Aviation Space and Environmental Medicine, 56*(8), 765–770.
  18. Armstrong, L. E., & Casa, D. J. (2009). Methods to evaluate electrolyte and water turnover of athletes. *Athletic Training & Sports Health Care, 1*(4), 169-179.
  19. Kunstel K. Calcium requirements for the athlete. Curr Sports Med Rep. 2005 Aug;4(4):203-6. doi: 10.1097/01.csmr.0000306208.56939.01. PMID: 16004829.
  20. Volpe S. L. (2015). Magnesium and the Athlete. Current sports medicine reports14(4), 279–283. https://doi.org/10.1249/JSR.0000000000000178
  21. Erem S, Razzaque MS. Dietary phosphate toxicity: an emerging global health concern. Histochem Cell Biol. 2018 Dec;150(6):711-719. doi: 10.1007/s00418-018-1711-8. Epub 2018 Aug 25. PMID: 30159784.
About the Author

Hanli is a Registered Dietitian with a special interest in sports nutrition. She has a Master's degree and is currently a PhD candidate focusing on adolescent athlete nutrition. She has published research in the Obesity Reviews journal and is a research coordinator at the Sport Science Institute of South Africa.

Want More Great Content?

Check Out These Articles