Electrolytes in a UK Heatwave: Who Needs Them and Who Just Needs Water
Every UK heatwave sends electrolyte sales vertical — and half of those buyers only needed a glass of water. Here's how to tell which camp you're in, because the answer changes with the weather, your training and your sweat.
The 60-second science
Electrolytes — mainly sodium, plus potassium and magnesium — keep fluid balanced between your cells and blood. Sweat costs you both water and sodium. Replace only the water after heavy sweating and you dilute what's left; that's why long-distance runners can get into trouble drinking plain water alone.
Water is enough when…
Normal days, desk work, exercise under ~60 minutes, moderate temperatures. Your kidneys and a normal diet handle it.
Electrolytes earn their place when…
- Training over an hour, or any intense session in heat
- Visibly salty sweaters (white marks on dark kit)
- Heatwave commutes, outdoor manual work, festival days
- Recovery from a stomach bug (pharmacy oral rehydration first for anything serious)
Formats
Tablets are cheapest per serving and travel well; powders let you scale the dose; ready drinks win on convenience. Check sodium per serving (300-500mg suits most sweaty sessions) and watch the sugar — some "hydration" drinks are soft drinks in gym kit.
Stock up in our electrolytes & hydration collection — free UK delivery, no minimum.
This article is for information only and is not medical advice. Supplements are not a substitute for a varied diet; talk to your GP or pharmacist before starting anything new, especially if you are pregnant, breastfeeding, on medication or buying for a child.
