Sodium, potassium, magnesium, and chloride regulate fluid balance, nerve conduction, and muscle contraction. The problem is not the mechanism. The problem is that most people consuming these products are nowhere near the threshold where they actually need them.

Most electrolyte drinks contain 500–1000mg per serving. But the average gym session produces less than half a litre of sweat. And most people eating a normal diet already consume 2000–3000mg of sodium per day from food. (Shirreffs & Maughan, 1998; Journal of Sports Sciences)

Genuine dehydration → electrolyte imbalance → impaired nerve and muscle function.

But for mild dehydration, the primary deficit is water, not electrolytes. The perceived “boost” most people feel from an electrolyte drink? In the majority of cases, that’s just rehydration. A glass of water would have done the same.

1. Exercise over 90 min with heavy sweating — this is when sodium losses become meaningful.

2. Sauna sessions — significant sweat volume in short time.

3. The day after drinking alcohol — a strong diuretic that depletes sodium and potassium.

4. Long-haul flights — cabin humidity is ~10–20%, genuinely dehydrating.

5. Loading before a very intense session in heat — pre-loading sodium improves fluid retention.

If none of the above apply, drink water.