Electrolytes: Why Plain Water Sometimes Is Not Enough
When training is long, sweat is heavy, or the day is hot, sodium and potassium become as important as the water you drink.
The hidden risk of pure water
In typical day-to-day life, plain water and a regular diet handle hydration fine. But during prolonged endurance work, in hot environments, or when sweat losses are heavy, drinking large volumes of plain water without electrolytes can dilute the blood's sodium concentration — a condition called exercise-associated hyponatremia.
It is rare but serious. Symptoms blur with dehydration (headache, nausea, confusion) which is why some athletes drink more water and make things worse.
A simple electrolyte strategy
Under 60 minutes of moderate activity: plain water works. 60–90 minutes: add a pinch of salt to your bottle, or include a salty snack at the halfway point. Over 90 minutes, or in heat: aim for 300–700 mg of sodium per litre, with some potassium and magnesium.
Off the field: most adults get enough sodium from food. Potassium and magnesium are where many fall short — leafy greens, beans, nuts and fruit close that gap quickly.
When to involve a clinician
Persistent muscle cramps that hydration does not solve, irregular heartbeat, or extreme thirst with high urine output deserve a blood test, not a sports drink. Electrolytes are personal — don't over-supplement.
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