UK health officials warn against overhydration as heatwave hits southern England

Temperatures across southern England are expected to reach 37 °C, surpassing the previous June high of 35.6 °C set in 1976. The UK Health Security Agency (UKHSA) has issued a health update urging people to drink about 6–8 cups of fluid a day, monitor urine colour for adequate hydration, and avoid excessive fluid intake that can lead to overhydration and electrolyte imbalance.

Registered dietitians Sejal Jacob and Kirsty Wood advise that, during a heatwave, appetite often drops, making water‑rich foods an important source of hydration. They recommend consuming foods such as watermelon, tomatoes, grapes, Greek yoghurt, homemade ice lollies, citrus fruits, courgettes, lettuce and berries, which provide both water and essential nutrients.

The guidance also highlights groups who may need more fluid – pregnant or breastfeeding women, physically active persons, and those recovering from illness – while cautioning against sugary drinks, high caffeine intake, and drinking beyond what the body signals.