Most people know they should drink more water. Far fewer understand why hydration is more complex than fluid intake, or why signs of dehydration often go unrecognised until they’re significantly affecting performance.

Electrolytes: The Forgotten Variable

Water follows sodium in the body. Without adequate electrolytes — sodium, potassium, and magnesium — the body cannot retain or distribute fluid properly. Drinking large volumes of plain water during heavy exercise can worsen hydration status.

Athletes, those training in heat, and anyone following a low-carbohydrate diet should pay particular attention to electrolyte intake. The headaches and fatigue of ‘keto flu’ are in most cases symptoms of electrolyte depletion.

Recognising Dehydration Before It Affects You

Thirst is a late indicator — by the time you feel thirsty, you’re already mildly dehydrated, and even mild dehydration measurably reduces cognitive performance and physical output.

Drinking 400 to 600ml of water first thing in the morning compensates for overnight fluid loss and improves morning energy. Pre-hydrating before training produces significantly better performance than trying to catch up after.