What you actually lose when you sweat

Stand outside in a Dubai July and you start sweating before you've decided to. That's the body doing its job: sweat evaporates, and that's how you shed heat. But sweat isn't just water. Dissolved in it are electrolytes — minerals your body runs on — and they leave with every drop.

Sodium leads, by a distance.

Of the electrolytes in sweat, sodium is the one you lose in the greatest amount — well ahead of potassium and magnesium. That's not a quirk, it's chemistry: sodium is the main electrolyte in the fluid outside your cells, so it's the one that shows up most in what you sweat out. Potassium and magnesium go too, in smaller amounts.

Heat changes the maths.

One workout is one thing. A climate where you're warm from the car park to the office to the evening padel court is another. You're not having one big sweat — you're having a long, low one, all day. The water you lose is obvious: you feel thirsty, you drink. The electrolytes that left with it are the part you don't see.

Water replaces the volume. Not the rest.

Plain water tops up the millilitres, but it doesn't carry back what was dissolved in what you lost. That's the whole reason electrolyte drinks exist — to put the minerals back, not just the fluid.

The authorised bit, said plainly: sodium, alongside the rest of the electrolyte trio, supports normal hydration. That is the job. We do not claim anything past it.

What this means for your bottle.

One SALT sachet in 750 ml of still water puts back 500 mg sodium, 200 mg potassium and 60 mg magnesium — the three you lose most, in amounts we print on the front of the pack and on this page. No proprietary blend. No "and fourteen other things." Just what left, going back in.

Authorised health-claim references: Sodium and the electrolyte trio support normal hydration.