Hydration Science: How Much Water Do You Really Need?
Evidence-based hydration guidelines, the factors that affect your daily water needs, and how to hit your target every day.
1. The Base Formula
Base (ml) = Body Weight (kg) × 35
+ 350 ml per 30 min of exercise
+ 250–500 ml for hot climate
+ 300–500 ml for pregnancy / breastfeeding
This formula aligns with WHO and EFSA hydration guidelines for adult men and women under moderate conditions.
2. Signs of Dehydration
- Mild: Thirst, dark urine (aim for pale straw), dry mouth, slight fatigue
- Moderate: Headaches, brain fog, reduced physical performance
- Severe: Dizziness, rapid heart rate, confusion — seek medical attention
3. Practical Hydration Tips
- Start each morning with a large glass of water to offset overnight losses
- Keep a marked 1-liter bottle visible on your desk as a visual reminder
- Set hourly reminders if you tend to forget to drink
- Include hydrating foods: cucumber (96% water), watermelon (92%), strawberries (91%)
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