What are Electrolytes? Fluid and Electrolyte Balance Explained

Everyone knows sweat is salty - but why?

When we lose bodily fluids by sweating, it is common knowledge that we need to replenish fluids by drinking water, but we also need to replenish the lost minerals and salts, which are known as “electrolytes.” You may have heard the term before, especially in relation to isotonic or sports drinks.

But what exactly are electrolytes, and what do they do for our bodies?

Electrolytes are minerals and salts that are dissolved into body fluids, such as sweat, blood, tears, and urine, that naturally carry either positive or negative electric charges. They are essential for many bodily functions, such as:

• Balancing water levels in your body

• Balancing your body’s (acidity/alkalinity) pH level

• Regulating muscle contractions

• Central nervous system function

• Transporting nutrients and waste in and out of cells

• Keeping heart rate steady and consistent, and maintaining stable blood pressure

• Keeping teeth and bones strong and healthy

Electrolyte Imbalances

An electrolyte imbalance occurs when the level of one or more types of electrolytes is too high or too low. The main cause of electrolyte imbalance is changes in fluid levels in your body, so it is important to take in the same amount of water that you lose through sweating and other bodily processes each day.

Try not to be dehydrated or overhydrated–balance is key.

Aside from fluid intake, other potential causes of electrolyte imbalance are:

• Heavy sweating (i.e. when doing prolonged or intense exercise)

• Vomiting and/or diarrhoea

• Certain medicines, or taking too many mineral supplements

• Problems in the heart, liver, or kidney

Since electrolytes are vital to many body functions, there are a variety of symptoms associated with an electrolyte imbalance, including:

• Fatigue

• Low energy

• Nausea

• Headache

• Muscle cramps

• Blood pressure changes

• General malaise

  
  

In Conclusion

It is important to stay hydrated and maintain a healthy diet for our bodies to maintain proper function. In particular, if you lose a lot of fluid, it is important to replace not only the water but also the electrolytes lost in the process.

References

Berman, Jacob, M.S., M.P.H. (2025, November 19). Electrolytes. MedlinePlus. https://medlineplus.gov/ency/article/002350.htm

Beswick, Kyle. (2019, October 16). What are Electrolytes? Cedars-Sinai. https://www.cedars-sinai.org/blog/electrolytes.html

Cleveland Clinic. (2021, September 24). Electrolytes. https://my.clevelandclinic.org/health/diagnostics/21790-electrolytes

Maughan, R. J., & Shirreffs, S. M. (1997). Recovery from prolonged exercise: restoration of water and electrolyte balance. Journal of sports sciences, 15(3), 297–303. https://doi.org/10.1080/026404197367308

Medline Plus. Fluid and Electrolyte Balance. NIH: National Library of Medicine. https://medlineplus.gov/fluidandelectrolytebalance.html