Electrolytes are often mentioned in training and hydration advice, but not always explained clearly. In this guide, we break down what electrolytes are, why they matter, and when you actually need to think about them in everyday life and training.
What are Electrolytes?
Electrolytes are minerals in your body fluids that help control hydration and keep nerves and muscles working properly. If you’ve ever had a blood test where sodium or potassium was mentioned, those are electrolytes. The main ones you’ll hear about are sodium, potassium, magnesium, calcium, chloride, and bicarbonate.
Why they matter
Here’s the simplest way to think about it: water is the base, and electrolytes help your body use that water properly.
When electrolytes, especially sodium, are low, you can drink plenty of water and still feel off. This balance between fluid and electrolytes is what people mean by hydration, and it’s explained clearly in this medical overview.
Electrolytes also play a role in how muscles and nerves function. When levels are out of balance, it can feel like cramping, twitching, weakness, or that heavy, flat feeling where your body just isn’t responding as it should. Cleveland Clinic explains this connection clearly here.
When you might need more electrolytes
Most people get enough electrolytes from food day to day. You’re more likely to need extra when you’re losing more fluid than normal.
1) You’re sweating more than usual
Training hard, long runs, HYROX, heat, travel, or time in a sauna all increase sweat losses. Sweat is water plus sodium. Replacing sweat with only water replaces the easy part and misses the sodium.
2) You’ve been ill
Vomiting or diarrhoea can strip electrolytes quickly. That’s why proper rehydration is more than just drinking water.
3) You keep drinking water but still feel flat
This is common. People feel tired or headachy, drink more water, and don’t feel better. Sometimes the missing piece isn’t more fluid, but minerals.
4) You’ve changed your diet
Large drops in carbohydrate intake can change how much water and sodium your body holds, especially in the first week. This is why some people experience headaches or lightheadedness early on.
For most people, this isn’t about using supplements all the time, just recognising when losses are higher than usual and responding to them.
Food sources that cover most electrolytes need
For most people, a normal diet covers a lot.
Common food sources include:
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Sodium: salted meals, soups, cheese, bread
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Potassium: potatoes, beans, bananas, yoghurt, leafy greens
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Magnesium: nuts, seeds, whole grains, dark chocolate
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Calcium: dairy or fortified alternatives, tofu
So no, you don’t need an electrolyte drink day to day. But food doesn’t always cover you when losses increase quickly, especially if you’re sweating heavily or recovering from illness.
We hope this helps clarify when electrolytes matter and when they don’t. For most people, it’s about matching intake to periods of higher loss, not constant supplementation.
If you have any questions, drop us a message on Instagram at @mnrlsuk.
