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By Cathy Daub, PT, CCE and CD(BWI) Water is essential to the human body.  In fact, the brain is 75% water.  Do you find yourself dehydrated very often?  A striking fact that may get you to think about drinking more water each day is that when you become dehydrated, your brain actually shrinks.1   An interesting study carried out on nine to eleven year old kids in Los Angeles and Manhattan found that nearly two-thirds of children were actually dehydrated.  Researchers wondered if this dehydration would affect their school performance.   One group of kids drank one cup of water before taking a test, and the other group drank no water.  The water group was found to perform significantly better on the test.  The conclusion: “Even children in a state of mild dehydration, not induced by intentional water deprivation or by heat stress and living in a cold climate, can benefit from drinking more water and improve their cognitive performance.2 If you are feeling dehydrated, it is already likely that your body is past the mild symptoms of being thirsty.  When dehydrated, symptoms are feeling sleepy, fatigued, decreased alertness, and confusion but the good news is that water absorption happens so quickly that the immediate effects are reversed - within five minutes from mouth to bloodstream, peaking at about 20 minutes.3  And if you like cold water, you are in luck because your body absorbs cold water faster than warm water. How do you know if you are dehydrated in addition to the symptoms above?  If you drink water and feel like peeing soon afterwards, your body is likely not so dehydrated.  But if you drink water and don’t pee for some hours later, it is likely your body really needed the water. You can get water in other ways besides drinking a glass of it. Fruits and vegetables, teas, coffee and soda water all contain water.  In fact, broccoli is mostly water.  You can also make your own sparkling water by adding a few drops of lemon, cucumber, mint, tangerine, or cinnamon stick. Water is especially important for pregnant women and women in labor.  A pregnant woman has nearly doubled her fluid plasma volume by the end of her pregnancy.  She needs to carry enough water to meet the needs for herself and her baby.  In her third trimester, the baby’s brain is growing faster than any other part of his/her body.  Adequate water intake helps to ensure healthy growth of the growing brain. How much water should we drink every day?  The current recommendation is five glasses of tap water per day. Tap water with a filter is the healthiest water we can drink.  The Environmental Working Group (EWG)  has analyzed all the water purification facilities in the USA.  Just go to and then type in your area code and up will come an analysis of the water you are drinking.  Bottled water is an unregulated industry and therefore is not as safe as people think, because it is likely to have chemical and microbial contamination.  Purchasing stainless steel water containers and using your filtered tap water will ensure the healthiest water you can drink.   Why not give your baby,  yourself, and your family the very best? Footnotes:
  1. Kempton MJ, Ettinger U, Foster R, et al. Dehydration affects brain structure and function in healthy adolescents. Hum Brain Mapp. 2011;(32(1): 71-9.
  2. Edmonds CJ, Burford D. Should children drink more water?:the effects of drinking water on cognition in children.  2009:52(3): 776-69.
  3. Peronnet F. Mignault D, da Souich P, et al. Pharmacokinetic analysis of absorption, distribution and disappearance of ingested water labeled with D20 in humans. Eur J Appl Physiol. 2012, 112(6):2213-22.
  4. Saleh MA, Abdel-Rahman FH, Woodard BB, et al. Chemical, microbial and physical evaluations of commercial bottled waters in greater Houston are of Texas.  J Environ Sci Health A Tox Hazard Subst Environ Eng. 2008; 43(4):335-47.