Your brain is approximately 75% water. A study published in the *Journal of Nutrition* showed that even mild dehydration (1.36% after exercise) significantly impaired mood and concentration while increasing the frequency of headaches.
#### The Volume Fallacy
It’s not just about how much you drink; it’s about how much you retain. Chugging plain water can actually flush out minerals, leading to further intracellular dehydration.
#### The Hydration Protocol
1. **The Morning Litre:** Drink 500ml–1L of water immediately upon waking to compensate for respiratory water loss during sleep.
2. **The Mineral Pinch:** Add a pinch of high-quality sea salt (sodium/magnesium/potassium) to your water to improve absorption.
3. **Calculate Your Needs:** Activity level and climate change your requirements. Check the [Water Intake Calculator](/water-intake-calculator/) for your personalized volume.
**Reference:** *Armstrong, L. E., et al. (2012). Mild dehydration affects cognitive performance and mood of men. British Journal of Nutrition.*