My colleague Jeff takes care of a plant in his office. Well, “takes care of” might more accurately mean, “mostly ignores.” Fortunately, Jeff's plant is kind enough to let him know by wilting in the most dramatic of fashions.
Now imagine if that were your brain. “Please,” you may be thinking, “I would never be so foolish as to let my brain (or, frankly, even that poor plant) wither like that!” Ah, but what if it didn’t need to be so visually dramatic? What if even moderate dehydration made us droop?
It’s summer. It’s hot. You often feel dehydrated and know to reach for water. But what if you don’t feel thirsty? Or what if you wave off the perceived dehydration and decide to just power through?
If that’s the case, you may be stuck in a bad cycle. Poor thinking may well be involved, as it turns out that even mild dehydration actually impairs your thinking. Moderate dehydration (losing about a liter of water) clearly impairs cognition. An NIH study this year concluded that “mild dehydration caused deficits in visual and working memory and executive function in healthy young women.”
Now, if you can, fast forward to the school year. What does dehydration look like there? Granted, you won’t be out taking a long, sweaty hike from chemistry to Spanish on a random Tuesday morning, but it is still easy to become dehydrated just by going about your day. Maybe you skipped breakfast, or you had to hurry from history to pre-calc, because your APUSH teach ran late in second period discussing the Progressive Era and you have a trig quiz in third period.
(Jeff’s plant without water. Jeff’s plant with water. Notice a difference?)
With all the bustle of your schedule, you might go half the day without making time to find a water fountain. And if you do that, there is a good chance you may sip enough water to slake your thirst rather than drinking enough to fully rehydrate. Does it really matter? Well, yes.
In another study, subjects were tasked with playing a complex card game with rules that consistently changed through the game. Sound like anyone’s school day? Or like navigating social situations? The game was designed to test impairment of executive functions, including tasks such as sustaining attention; organizing, planning and prioritizing; maintaining focus; emotional and mental flexibility; and self-monitoring. All of which are essential for success in school, work, or relationships. What effect did dehydration have on the subjects? Well, “when the women were dehydrated, they had about 12 percent more total errors” in the game, according to the study’s author, Dr. Nina Stachenfeld of the Yale School of Medicine.
To learn more, and to answer many of the questions you may have about proper hydration, grab a glass of water and check out this pretty comprehensive piece on NPR.