Wednesdays are called hump day for a reason—and it’s not because people are getting hot and heavy. The weekend is so close you can taste it. So naturally it becomes harder to concentrate at work when all you can think about is how much you can’t wait to sleep in on Saturday morning.

A new study confirms that our response time and memory tank after we hit the 25-hour mark of the workweek. For most of us, that’s Wednesday night. Our bodies (and brains) weren’t made to operate at peak performance for the 40-plus hours most of us work every week. So next time you notice yourself making sloppy mistakes, take a break. It’ll help you and your company.