Updated
Updated · The Guardian · Jun 28
Experts Urge 300-500ml Morning Water in 35C-Plus Heat, Doubt Electrolytes for Most
Updated
Updated · The Guardian · Jun 28

Experts Urge 300-500ml Morning Water in 35C-Plus Heat, Doubt Electrolytes for Most

3 articles · Updated · The Guardian · Jun 28

Summary

  • 300-500ml of water on waking can help offset dehydration after hot nights, with experts saying 70-80% of people may start heatwave days already behind on fluids.
  • Above 35-36C, sweating becomes one of the body’s only effective cooling tools, and thirst often arrives after a 1-2% body-fluid loss that already signals mild dehydration.
  • Regular water intake through the day remains the main advice: drink moderate amounts frequently, use urine color as a rough guide, and aim for 500-750ml an hour during intense exercise.
  • Tea, coffee, sparkling water, juice and milk can all hydrate, but alcohol quickly turns dehydrating after one low-ABV drink and cold beverages may not cool the body as much as people assume.
  • Electrolyte drinks are usually unnecessary unless activity lasts more than 60 minutes in heat or sweating is heavy, though overdrinking plain water can rarely trigger low-sodium hyponatremia.

Insights

As heat-related deaths soar, is focusing on personal hydration distracting from the urgent need to redesign our cities for survival?
If a 2026 study shows correcting low sodium offers no benefit, is our approach to severe dehydration fundamentally flawed?