Electrolytes: Why Plain Water Is Not Always Enough

For most people on most days, plain water is entirely sufficient, and the electrolyte sachet is a well-marketed solution to a problem they do not have.

When they genuinely help

• Long or intense exercise, especially in heat, where you lose a lot of sodium in sweat.
• Illness involving vomiting or diarrhoea.
• Very hot days with heavy sweating and little food.

The rest of the time

A normal diet supplies the sodium, potassium and magnesium you need. Adding more salt to your water on a desk day is unlikely to do anything useful, and a high sodium load is one of the more reliable ways to feel puffy the next morning.