If you’ve been skimping on sleep for a few days, your instinct might be to spend a few extra hours under the covers the next night to make up for it. But that might not bring you the benefits you may think: Catching up on sleep might drain your brain, a new study from Baylor University found.

The researchers had 28 college students complete a sleep diary and wear sleep-monitoring devices for one week. They discovered that that sleep variability—nights of short sleep followed by longer, “catch up” nights—was linked to worse scores on tests of attention and creativity.

What’s more, the more variability they showed in their sleep schedules, the more their creativity and executive attention—the intense focus necessary for planning, making decisions, and correcting errors—declined over the course of the week, the researchers say.

Short, irregular sleep can mess with your REM cycles, the part of sleep that helps us creatively use the information we already have on file.

So if you have a project that requires some serious brainpower, you might want to work on keeping a constant sleep schedule in the days that precede it.

But yo-yo sleeping doesn’t just mess with your creativity: It can make you feel even more tired, too.

That’s because it pushes back your body’s internal clock, or circadian rhythm, which messes with your ability to fall asleep at your normal time. As a result, you’ll end up feeling fatigued the next morning, as we reported.