Our brain must be properly hydrated if it is to function properly.  In fact our whole body needs water. Just look at the facts below:

Our Brain is 75% water / Moderate dehydration can cause headaches and dizziness
Water is required for expiration
Regulates body temperature
Carries nutrients and oxygen to all cells in the body
Blood is 92% water
Moistens oxygen for breathing
Protects and cushions vital organs
Helps to convert food into energy
Helps body absorb nutrients
Removes waste
Bones are 22% water
Muscles are 75% water
Cushions joints

 

Some tips:

Don't overdo it. Take time throughout the day for a glass of water whether or not you feel you need it. If you wait until you feel thirsty, you're already experiencing the signs of dehydration. Don't substitute pop or juice as a proper beverage to prevent dehydration. Many other drinks contain sugar and caffeine which may speed up dehydration, as well as other additives which may have a detrimental effect.
 

Our Brain - promoting brain-friendly learning

Bryn Evans 2003