One hallmark of dehydration is the dreaded dehydration headache. It’s caused by losing too much water, so the solution seems obvious. Just grab the nearest water spigot and let it rip, right? Actually, as is the case with most health issues, headaches aren’t that simple. Dehydration is just one star in a vast galaxy of headache causes.

Overhydration can also cause headaches. You rarely hear about it, but I’m willing to bet you’ve felt it before. Drinking too much water in a short timeframe can result in acute sodium imbalance, and can cause or worsen a headache. Many endurance athletes—who are often encouraged to drink beyond thirst—run right past the warning signs and wind up with a dangerous condition of low blood sodium called hyponatremia.

Thankfully, there’s a simple strategy you can follow to both prevent and remedy headaches if they’re caused by dehydration or overhydration. Simply consume your water with a significant portion of sodium. In two words: electrolyte drinks.

But as I mentioned earlier, it’s important to approach the topic of headaches with nuance. So in this article, I’ll cover both dehydration and overhydration, the role of electrolytes, and a few other common causes of headaches.