You know that image of a person staggering through desert, barely able to speak and hallucinating a mirage in the distance? That’s the extreme way dehydration affects the mind. After all, drinking fluids is crucial to maintaining every system in your body, including your heart, brain and muscles. And just being somewhat parched—after a workout, a walk in the summer sun or a some weekend yard work—can take a serious toll on your body and reflexes due to a dip in brain function.
Cognitive function wilts as water departs the body, a study from the Georgia Institute of Technology found. The data pointed to functions like attention, coordination and complex problem solving suffering the most. It turns out, our neurons are largely made up of water. When the body is deprived of water, it affects how well signals are transmitted and received in the brain and your concentration takes a hit. That’s when mistakes or accidents occur.
In their study, it was abundantly clear that tasks that require constant attention were the most impacted, according to Mindy Millard-Stafford, a professor in Georgia Tech’s School of Biological Sciences and the study’s principal investigator. “Maintaining focus in a long meeting, driving a car or a monotonous job in a hot factory that requires you to stay alert are some examples,” she says. “Higher-order functions like doing math or applying logic also dropped off.”
Call it dry brain. You start to feel sluggish, and both your mood and energy drops. “There’s already a lot of quantitative documentation that if you lose two percent in water it affects physical abilities like muscle endurance or sports tasks and your ability to regulate your body temperature,” says Millard-Stafford. Now, it’s clear that it’s inhibiting your concentration as well.
This begs the question: Just how much water should we be drinking? Like with anything in health, it’s not as simple as we’d like it to be. Every body is different. So is every day. That “rule” to drink eight, 8-oz glasses of water a day doesn’t have a lot of scientific evidence behind it, but it’s not necessarily a bad recommendation.
The National Academies of Sciences, Engineering and Medicine aim a bit higher, saying that men “who appear to be adequately hydrated” consume approximately 125 ounces per day. But they acknowledge that nearly 20 percent of your day’s hydration is derived from food, which can be difficult to count.
The key is to drink regularly. And if you don’t naturally hydrate as much as you should, consider water-rich foods like fruits and vegetables. Especially during the warmer summer months. It’s important to remember that if you’re feeling thirsty, you’ve already waited too long to drink some water.