©Arlene R. Taylor PhD
“The brain is supposed to be three-quarters water,” the voice said, “so that should allow for plenty of water on the brain.”
The phrase water on the brain took me back decades to a nursing-school lecture about hydrocephalus—described back then as water on the brain.
Tuning back into the conversation I heard the voice continue with, “I mean, the brain is filled with water so how come people are concerned about dehydration? And anyway, how could there be a connection between dehydration and brain function?”
Excellent questions, all, and we dialoged about the brain, the implications of dehydration, and the importance of adequate hydration for optimum brain function and energy.
The caller was correct in that the brain is composed of at least three-quarters water, although estimates are that it may go as high as 85 to 88 percent water, unless the person is dehydrated. That is very different from the concept that water on the brain implies storage capability. The brain has no way to store water so dehydration impacts not only the size of your brain but also how well it functions. According to the Mayo Clinic, the average adult loses more than 80 ounces of water every day through breathing, sweating, and eliminating wastes—that’s the equivalent of ten eight-ounce glasses!
Dehydration is believed to be a big problem for the brain. Researchers in the United Kingdom studied the brains of teenagers after 90 minutes of cycling. Some of the teenagers wore light shorts and t-shirts while others wore sweat-inducing clothing. No surprise, the teenagers who wore the sweat-inducing clothing lost the most weight: about two pounds in sweat. They also had the most shrinkage of brain tissue. Scans showed the brain tissue had actually shrunk away from the skull. Just 90 minutes of continuous sweating shrunk the brain as much as an entire year of age-related wear and tear.
The brain had to work harder to process information, too. The teenager participants were asked to play a computer game designed to test their ability to plan and solve problems. The teenagers who wore the sweat-inducing clothing performed just as well (as the lightly-glad teenagers) but scans showed they had to use more of their brain power to do so. The good news? After drinking replacement water, brain size and hydration returned to normal, which points to the need for adequate water intake during activities that result in profuse sweating.
The implications of this study for cognitive thinking are staggering. Brain dehydration may be a factor influencing not only performance of students in school but brain function in the workplace. Lack of an adequate and ongoing supply of water to the brain has been found to impair short-term memory, the recall of long-term memory, ability to do mental arithmetic, and the ability to focus and pay attention, to name just a few. If you want to keep your wits about you, it appears you do need to take in adequate fluid on a regular basis.
Studies by the founder of the Advanced Learning and Development Institute, Dr. Corinne Allen, revealed that cells in the brain need twice the energy compared to cells in other parts of the body. Water is believed to be key in providing some of this needed energy. Water is also required for the production of vital hormones and brain chemicals such as neurotransmitters. These substances are absolutely essential for thinking. Just the transmission of information among neurons may utilize half of all the brain’s energy.
If your goal is to maintain optimum body weight, avoiding dehydration may be critically important. Dehydration has been found to slow down the metabolic rate by as much as 3 percent. According to Sandra Gibson, more than a third of Americans have suppressed their thirst mechanism to the point where it is often misinterpreted as hunger—so they eat when actually their brain and body are craving water. By the time you feel thirsty you have lost between 1 percent and 3 percent of your total water content. The number one reason for daytime sleepiness and low energy is dehydration. Again, this suggests the importance of drinking water on a regular basis and not just in response to a sense of thirst.
For most people, the longest span of time without drinking water occurs during sleep. Since I need nine hours per night—I do not wake up and drink water—one of my first activities in the morning involves drinking twelve ounces of pure water. I prefer filtered, slightly alkaline water, and often add a package of crystalized lemon to the water, as well. I drank twelve ounces this morning just before I began writing this article. Now that it is finished, I think I’ll have another twelve ounces and get some more water on my brain.
Note: If you have a medical condition that may require limiting your intake of water, be sure to contact your healthcare professional prior to making lifestyle changes.