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Why Your Brain Needs Water

Water enhances mental function and is essential to survival

water faucet

On most mornings, one of the first stops through my waking-up routine is the kitchen cupboard, where I keep my cups and other drinking vessels. Even if I'm not particularly thirsty, as a student of the brain, I'm convinced of the value of drinking enough water. Of all the tricks I've learned for keeping my mind sharp, from getting enough sleep to doing crossword puzzles, staying hydrated may be the one I follow most closely, partly because it's so easy to get a drink whenever I'm thirsty. This is a convenience to be grateful for.

Our brains depend on proper hydration to function optimally. Brain cells require a delicate balance between water and various elements to operate, and when you lose too much water, that balance is disrupted. Your brain cells lose efficiency.

Years of research have found that when we're parched, we have more difficulty keeping our attention focused. Dehydration can impair short-term memory function and the recall of long-term memory. The ability to perform mental arithmetic, like calculating whether or not you'll be late for work if you hit snooze for another 15 minutes, is compromised when your fluids are low.

Over the course of a typical twenty-four hour period, the longest spell most of us go without fluid intake is the six to eight hours we spend sleeping. Sleeping is hardly the kind of activity that you sweat over, but that doesn't mean you're not losing water during the night. With every somnolent breath, you expel moisture, and the cumulative effect of a night's sleep is to dry out.

It's for this reason that I habitually get a drink soon after I wake up. If you're like me, when you're simply reminded of the negative effects of dehydration, your next thought is to head for the water cooler.

If we want to have our wits about us, we've got to take in fluid. Imagine, as you think about how important water is to your own daily functioning, what life might be like if your access to it was restricted. Perhaps you usually drink bottled water. Imagine it did not exist. You would get thirsty enough, eventually, to drink from the tap. It's always there, at your disposal. But suppose the nearest tap were 5 miles away. That's not such a long distance, except you don't have a car. And it's hot outside, like 101 F. Now how motivated are you to walk that long way in the sun? What if you've got a thirsty child?

Unsafe drinking water

If water is important to you, not because you're parched, but just because you want to function optimally, imagine how much more some humans are forced to endure just to get the minimum daily requirements of water. Living in the developed world is like drinking a nepenthe: it's easy to forget that others are far less fortunate. While your thirst is quenched, almost a billion people on the planet don't have access to clean drinking water. 38,000 children under the age of 5 die each week because they lack uncontaminated water. African women walk over 40 billion hours each year carrying cisterns weighing up to 18 kilograms to gather water, which is usually still not safe to drink.

So, if you've had enough water today to keep your brain running, perhaps you can do something that will help your heart overflow, too. Give the gift of water to those who don't have it, but desperately need it. Consider making a donation to charity: water at Even $5 helps.

October 15 is Blog Action Day, and the topic this year is water. You can follow the conversation here.

Do you have any thoughts about this problem? Aside from donating to charity, what are the best steps we can take to help get water to those who need it? Any changes we can make in our daily life?

Click the link below and support the UN's efforts to bring clean, safe water to millions.|Start Petition

Source material:

Bezprozvanny, Ilya, and Mark P. Mattson. "Neuronal calcium mishandling and the pathogenesis of Alzheimer's disease." Trends in neurosciences 31.9 (2008): 454-463.

Ganio, Matthew S., et al. "Mild dehydration impairs cognitive performance and mood of men." British Journal of Nutrition 106.10 (2011): 1535-1543.

Adan, Ana. "Cognitive performance and dehydration." Journal of the American College of Nutrition 31.2 (2012): 71-78.

Tweedle, Charles D., and Glenn I. Hatton. "Ultrastructural comparisons of neurons of supraoptic and circularis nuclei in normal and dehydrated rats." Brain research bulletin 1.1 (1976): 103-121.

Madeira, M. D., A. R. Lieberman, and M. M. Paula-Barbosa. "Effects of chronic alcohol consumption and of dehydration on the supraoptic nucleus of adult male and female rats." Neuroscience 56.3 (1993): 657-672.

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