Electrolyte drinks have had a remarkable decade. What began as a product marketed to elite athletes has become a daily staple for people who go to the gym occasionally, work in an office, and do not sweat particularly heavily. The marketing has been effective. The word 'hydration' now implies something more than simply drinking water, and many people genuinely believe that plain water is insufficient for everyday hydration. The evidence, however, tells a more nuanced story.
Electrolytes are minerals that carry an electrical charge in solution: primarily sodium, potassium, chloride, magnesium, and calcium. They regulate fluid balance, nerve signalling, muscle contraction, and how the kidneys handle water. The key physiological point is that when you drink plain water, a fall in plasma sodium concentration reduces the drive to drink and increases urine output, meaning that without electrolytes, restoration of fluid balance after significant losses is slower and less complete. Electrolytes, particularly sodium, help the body retain the fluid it takes in.
This matters most in specific circumstances. For exercise lasting more than 45 to 60 minutes, particularly in heat or at high intensity, electrolyte replacement alongside fluid becomes more important. As you will know by its salty taste, sweat is not pure water… it contains sodium. Replacing fluid without replacing electrolytes in prolonged exercise can dilute plasma sodium to dangerous levels, a condition called hyponatraemia. This would be rare for people living in a typical British climate who do not participate in prolonged exercise or sweat excessively. For illness involving vomiting or diarrhoea, where both fluid and electrolytes are lost rapidly, oral rehydration solutions are clinically important, particularly in children, the elderly, and those who are already unwell.
For the average person going about daily life, however, working, doing an hour or less of moderate exercise, not sweating profusely…. then plain water is entirely sufficient for hydration. The Harvard T.H. Chan School of Public Health has stated plainly that there is no evidence electrolyte drinks are a healthier choice than water for the average person. A balanced diet already provides adequate electrolytes for normal daily needs. The added sugar in many commercial sports drinks is a legitimate concern, particularly when consumed habitually without the calorie expenditure to offset it, and the dental erosion associated with their low pH is well documented.
The practical conclusion is straightforward: water is the right choice for everyday hydration and for exercise lasting less than an hour. Electrolyte drinks earn their place during prolonged or intense physical activity, in hot conditions, during illness, or for people with specific medical conditions that affect electrolyte handling. If you enjoy them, and the flavour genuinely helps some people drink more, which is not without value.. then choosing lower-sugar formulations reduces the downside. BUT the idea that ordinary water is somehow deficient for ordinary life is a marketing claim, rather than a physiological one.
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References:
1. Millard-Stafford M, et al. The Beverage Hydration Index: Influence of Electrolytes, Carbohydrate and Protein. Nutrients. 2021;13(9):2933. PMC8465972
2. Nish A. Water vs. Sports Drinks: What's Best for our Bodies. UnityPoint Health. 2024.
3. Harvard T.H. Chan School of Public Health, The Nutrition Source. Electrolyte Drinks. 2025. Available from: https://nutritionsource.hsph.harvard.edu/electrolyte-drinks/