You're probably coding dehydrated (and losing 25% of your output)

There's a gap between when you're impaired and when you actually feel thirsty.

Researchers who study hydration keep coming back to this problem. Thirst is a late indicator. By the time you notice it, your brain has already been running slower.

The numbers are uncomfortable

A study published in the Journal of Nutrition found that just 3-4% dehydration leads to a 25% drop in work performance.

That's not an extreme edge case. That's what happens during a normal afternoon if you skipped your morning glass of water and got lost in a coding session for a few hours.

It gets worse. Even at 1% dehydration - far below the thirst threshold - research shows cognitive functions start slipping. Processing speed. Short-term memory. Decision-making. The exact things that make programming hard.

Your brain is about 75% water. When the water level drops, signal processing slows. You don't notice it happening because your brain doesn't have a dehydration dashboard. You just feel a bit foggy, a bit slower, a bit more prone to small mistakes.

Why developers are especially bad at this

When you're in flow, you're not thinking about water.

You're thinking about the function you're trying to get right, the bug you've been tracking for 90 minutes, or the PR you need to finish before end of day. A glass of water isn't part of that mental model.

So hours go by. The glass you filled in the morning is still sitting there, half-empty or untouched. And you wonder why your focus has gone sideways after lunch.

Coffee makes this worse. Caffeine is a mild diuretic. If you're running your afternoons on espresso shots and nothing else, you're probably digging a deeper hole.

The fix is straightforward

Drink water before you're thirsty.

The research is pretty clear that front-loading hydration - starting your day well hydrated and maintaining it throughout - is more effective than trying to catch up after you've noticed the fog.

Regular breaks help with this. When you step away from the screen every 25-30 minutes, you have a natural moment to drink something. The movement itself isn't the only benefit. Getting up, walking to the kitchen, refilling a glass - that whole routine keeps hydration consistent in a way that willpower alone doesn't.

I use Movedoro for the movement breaks, but a real side effect is that I drink a lot more water than I used to. The breaks create the opportunity.

That's pretty much it.