Water, coconut water or electrolytes
The hydration market is full of products making overlapping claims. Understanding what each one actually contains and what that means for different situations lets you choose the right one rather than the most marketed one.
Plain water is the appropriate hydration solution for the majority of everyday situations: sedentary or light activity in a temperate environment, fluid replacement after a normal night's sleep, drinking between meals when dietary electrolytes are adequate. It hydrates effectively when electrolyte stores are not depleted, because food provides the sodium, potassium and magnesium needed to maintain the osmotic environment for cellular water absorption. The cases where plain water is insufficient are specifically those where significant electrolyte losses have occurred alongside fluid losses: sustained physical work in heat, prolonged aerobic exercise, illness with vomiting or diarrhoea, significant alcohol consumption and, to a lesser extent, long-haul air travel.
What is happening
Coconut water is often marketed as a natural electrolyte drink and is genuinely higher in potassium than most commercial sports drinks, containing around 600 milligrams of potassium per 330 millilitres. However, it is low in sodium, containing around 40 to 60 milligrams per serving, which limits its utility as a hydration solution after significant sweating where sodium loss is the primary electrolyte deficit. It also contains around 15 to 20 grams of natural sugars per serving. As a general hydration drink for light activity, it is adequate and better than sugary alternatives. As a targeted electrolyte replacement after heavy sweating or illness, its sodium content is insufficient without additional sodium sources.
Commercial sports drinks like Lucozade Sport, Gatorade and Powerade are formulated to provide a specific sodium and carbohydrate combination designed for fluid absorption during prolonged exercise. The sodium content of 300 to 500 milligrams per 500 millilitres drives water absorption via the sodium-glucose co-transporter mechanism in the small intestine, which is faster than osmosis-driven water absorption from plain water alone. The carbohydrate content provides fuel for sustained exercise. This formulation is appropriate for activities lasting more than 90 minutes at moderate to high intensity. For general shift work hydration, the caloric and sugar content of full-strength sports drinks is unnecessary and the sodium content, while better than coconut water, is still below optimal for significant sweat losses.
What to do next
Dedicated electrolyte supplements, available as tablets, powders or sachets, are typically low or zero calorie and contain sodium, potassium and magnesium in quantities calibrated for hydration rather than energy provision. The sodium content in quality formulations is typically 500 to 1000 milligrams per serving, covering the primary electrolyte loss from a moderate shift with physical activity. These are the most targeted option for hydration without unnecessary caloric load. They work equally well in hot or cold water and do not require the high sugar content that commercial sports drinks use as a co-transporter mechanism. For someone who wants electrolyte-enhanced hydration across a working shift without the calories and sugar of sports drinks, a dissolvable electrolyte supplement added to water is the clearest choice.
Related reading: Heat and sun hydration, Hydration basics, Hydration at work.
Sources: EFSA water guidance, EUFIC hydration guidance, WHO physical activity guidance, WHO healthy diet guidance.
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