Electrolytes explained

The key electrolytes

Sodium

The main electrolyte lost in sweat. Sodium holds fluid in the bloodstream, drives thirst and supports nerve signalling, which is why plain water alone can leave you feeling flat after heavy sweating.

Potassium

Works alongside sodium to keep fluid balanced inside your cells and supports normal muscle contraction, including the heart.

Magnesium

Involved in hundreds of enzyme reactions, including energy production and normal muscle function. Commonly under-consumed in everyday diets.

Calcium

Needed for muscle contraction and nerve transmission as well as bone health.

Chloride

Pairs with sodium to maintain fluid balance and normal blood pH.

Zinc, manganese & vitamins C and D

Support normal immune function, energy metabolism and protection of cells from oxidative stress — the everyday background work that keeps training consistent.

What are electrolytes?

Electrolytes are minerals that carry an electrical charge when dissolved in water. Your body uses that charge to move fluid across cell membranes, fire nerve signals and contract muscles. Sodium, potassium, magnesium, calcium and chloride are the ones that matter most for hydration.

Water is only half of hydration. Fluid follows minerals, so if you drink a lot of water without replacing the minerals you've lost, your body can struggle to hold on to it — you drink more and simply pass more through.

Why you lose electrolytes

Sweat is the big one. Sweat is mostly water and sodium, with smaller amounts of potassium, magnesium and calcium. How much you lose depends on how hard you're working, how hot and humid it is, how acclimatised you are, and your individual sweat rate — which varies widely between people.

Training isn't the only cause. Heat, long-haul flights, illness involving vomiting or diarrhoea, high-caffeine days, alcohol and simply under-eating minerals can all leave you short.

Signs you may be low

Common signs of dehydration or low electrolytes include thirst, dark urine, headache, dizziness when standing, fatigue out of proportion to the effort, muscle cramps or twitching, and a heart rate that feels higher than usual for the same pace.

These signs are general and can have other causes. If symptoms are severe, persistent, or you have a medical condition, are pregnant or take medication, speak to a doctor or pharmacist rather than self-treating.

Electrolyte drinks vs. sports drinks vs. water

Plain water is perfect for short, easy sessions and everyday sipping. A dedicated electrolyte drink adds back the minerals sweat takes away without loading you with sugar. A traditional sports drink is really a carbohydrate drink — it's built to deliver fuel during long endurance efforts, and the electrolytes are secondary.

If you want the minerals without the sugar, an electrolyte mix is the simpler choice. If you're going long and need calories, you may want both.

How to use electrolytes

Before: a serving 20–30 minutes before a hot or hard session tops you up so you start balanced rather than playing catch-up.

During: sip steadily through long, hot or sweaty efforts instead of drinking a lot at once.

After: replacing sodium alongside fluid helps you retain what you drink, which is why a post-session serving often feels better than water alone.

Everyday: desk days, travel, hot weather and poor sleep are all reasonable times to use a serving — hydration isn't only a training thing.

What to look for on the label

Check the sodium content — this is what most "hydration" powders skimp on. Look for a full mineral profile rather than sodium alone, and check the sweetener: a drink loaded with sugar or artificial sweeteners defeats the point for a lot of people.

Every Spark blend is made with no sugar, no artificial sweeteners, 100% natural ingredients, and is vegan-friendly.