It is common-place now for sporty people to talk about electrolytes, electrolyte balance and restoring lost electrolytes after exercise. But what does this mean? Why are electrolytes important? And how does it affect you?

This two-part series will explain the basic background in what electrolytes are and why they are important and how to optimise electrolyte levels for maximum performance and recovery.


It is all too easy to get bogged down in fancy scientific terminology when talking about electrolytes, which can lead to people new to exercise (or people who are either not scientifically minded or simply don’t care about the science) to dismiss it as not being important. If you only take one thing away from this article, it’s that they are very important indeed! Think of your car. It needs petrol to run, right? Think of this as the food and water that you need to fuel your body during exercise.

But what about the oil in your car? Essentially you don’t need oil in your car for it to drive but without it your car will be a rusted heap very quickly. When you get an oil leak you have to fill up the oil tank so that the engine can run optimally (as well as repair the leak hopefully!).

Exactly the same can be said for electrolytes, they are needed for a whole host of things in the body including digestion, the amount of water in your body and control of muscles.

The importance of electricity                    

Before we explain electrolytes, it is really important to know that the body is basically like a computer that is controlling a motor and speeds that are controlled by the user. The computer needs electricity to process the signal coming in from the mouse or keyboard, and needs more electricity to process and send the signal to the motor, which then moves at the specified speed.

But our motor wouldn’t move because it needs another power supply to do the actual moving of the wheel. That is basically what the human body does – it uses electricity to transfer information from the brain to the muscles and more electricity is needed to contract the muscles that are being asked to work.

What are electrolytes?         

In its broadest sense, the word electrolyte means a substance that is able to become ionised when in a solution. What this means is that the substance is able to carry an electric charge when it is dissolved in water (blood is mostly water). This is the key.

Contrary to popular belief, water by itself doesn’t conduct electricity very well at all! It needs electrolytes to carry the charge through it, which is what happens in the blood when there are the right amounts of electrolytes dissolved in it. This allows the message to reach the muscles.

Why are electrolytes important_02

What do they do?

Electrolytes are also responsible for muscle contraction. Basically the differences between charges inside compared to outside the muscle create a reaction that causes the muscle to contract (this happens at a super-fast pace and involves lots of other physiological processes, but electrolytes are essentially the key to the whole thing), so an imbalance of these could cause the muscle to either over contract (or keep contracting uncontrollably, which is a cramp), or under contract, which can lead to under-performance.

One other thing that electrolytes (particularly sodium and chloride, AKA salt) do is tell the kidneys how much water should be in the body. Too much salt can lead to too much water being in the body. Although this may sound like a good thing (you may conclude that water is essential to life, which is true, and therefore more is better), it can lead to a host of medical problems, including a condition called oedema, which is the swelling of parts of the body due to too much water.

This has been known to happen to athletes who take salt tablets before races; their hands and feet swell so much they can’t compete.

Different types of Electrolytes

There are many different types of electrolytes, each with individual roles within the body, these include: sodium, chloride, magnesium and potassium and calcium (there are lots more too) and generally are well controlled in the body; the body has hundreds of mechanisms that control electrolyte levels.

Part 2 looks at what happens to certain electrolyte levels as you exercise and what you can do to optimise these before, during and after a workout/race.

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