Electrolytes are used every day in the human body. When we talk about electrolytes, we mainly talk about sodium, potassium, magnesium, and calcium. But what does each electrolyte do in the body and which ones should you be focusing on?





Sodium is the most important electrolyte in the human body. It is used for the contraction of muscles, conducting nerve impulses and general human function. Because of this, ensuring that you replace sodium is a must.


In terms of hydration, sodium is used by our body to regulate how hydrated we are. The higher the concentration of sodium there is compared to water in our body, the more dehydrated our body perceives us as being. Because of this, if we end up sweating out a lot of sodium without replacing it, our body can misread our hydration status and assume we are more hydrated than we actually are, preventing us from hydrating as efficiently as we possibly could.


Interestingly, a recent study suggested that sodium played such as large function in exercise, that when only 20% of sodium was replaced in a medium-distance triathlon compared to 70% of salt being replaced, the runners has decreased result times of 26 minutes on average [1].




Potassium is likely the electrolyte you hear the most about after sodium in terms of rehydration. It also plays various roles in the body such as muscle contraction, maintaining proper fluid balance, nerve transmission, and maintaining blood pressure. However, the amount of potassium we sweat out is significantly less than the amount of sodium and therefore we do not need to replace as much compared to sodium. The amount of potassium individuals sweat out varies, however, the average person will sweat roughly 150mg per litre.


You may notice that many companies will advertise high amounts of electrolytes but reach these goals by adding in significantly higher amounts of potassium compared to what is needed. This will not lead to better hydration and should be considered when choosing your electrolyte supplements.




Magnesium is commonly seen as the cure for muscle cramps but plays multiple roles in the body including energy production, muscle and nerve function, protein synthesis, and maintaining a healthy heart rhythm. Magnesium is also lost in small amounts in sweat.





The last electrolyte we commonly discuss is calcium. Calcium is important for healthy bones and is involved in muscle contraction, blood clotting, nerve function, and enzyme function. By replacing calcium, we can make sure that there are no deficits and therefore make sure that we are functionally optimally and maintaining healthy bones.


As an additional tip, if you are looking to supplement calcium to improve bone health, consider ensuring you are getting adequate amounts of vitamin D through spending more time outdoors or taking a vitamin D supplement.


References (DOIs)


[1] 10.1111/sms.12427


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