brain

The human brain cell can hold 5 times as much information as an encyclopedia.Your brain uses 20% of the oxygen that enters your bloodstream, and is itself made up of 80% water. Though it interprets pain signals from the rest of the body, the brain itself cannot feel pain….The 80% water sounds like a good enough reason to stay hydrated to me!!

You can use the hydration calculator at the link below to find out how much water you should be drinking every day:
http://bebrainfit.com/lifestyle/nutrition/brain-nutrition-basics-3-nutrients-you-cant-live-without/