Dehydration, as we all know, is bad for your physical health, whether you’re a young rapper or an elderly ex-President. But while the physical effects of dehydration are bad, it turns out that there are more subtle mental effects. Yes, dehydration, in addition to all the horrible things it can do to your body, also makes you stupid.
Granted, we’re not talking halving your IQ here, according to an in-depth look by NPR. But Mindy Millard-Stafford, the director of the Exercise Physiology Laboratory at Georgia Institute of Technology, found some pretty scary effects on your brain from being parched. Millard-Stafford assembled a meta-analysis of 33 studies and found that as little as 1.5% dehydration, essentially how much you sweat off after an hour-long hike in the summer heat, knocks you off your mental game. Interestingly, it was the high-level cognitive tasks that took the hit, things like paying attention or working on detailed tasks. One study found a 12% increase in errors amongst women playing a complicated card game, which isn’t a problem at your local Magic draft but is probably not a margin of error you want your brain surgeon to add on.
This isn’t conclusive and Millard-Stafford is clear that some of these studies have flaws (such as being funded by bottled water companies despite the experimental design and results being kept independent). And it’s not clear why a lack of water might dumb you down. Is your brain distracted by trying to get you hydrated? Or is this an independent problem due to the lack of water in your system? Either way, it makes sense to keep a water bottle around (although remember that you get 20% of your water from the food you eat). Also, remember that you can’t take a pee break during a long meeting, so maybe have a small cup beforehand to focus, and hammer the whole Nalgene afterward.