The science of everyday hydration (it isn't just water)

Hydration is not simply about volume. Water moves into cells only when the right mineral gradient exists — and that gradient is created by electrolytes: sodium, potassium, magnesium and chloride.

When you sweat, you lose far more sodium than most people assume: roughly 800–1500 mg per litre for the average adult. Replacing that fluid with plain water dilutes remaining sodium levels, which is why you can drink steadily all day and still feel flat.

A practical routine looks like this: start the morning with 400–500 ml of water containing electrolytes, drink to thirst through the day, and add a second serving on days with heat, travel or training over 60 minutes.

What matters most is consistency rather than intensity. Hydration compounds quietly — better focus, steadier energy, fewer afternoon slumps, and noticeably faster recovery after exertion.