Editors’ note: Here’s one of our favorite stories from the archives, now being featured in our Smarter Living collection.

Want to be more productive? Keep your nose to the grindstone, or your fingers on the keyboard and your eyes on the screen. Because the more time you put in, the more you’ll get done, right?

Wrong. A growing body of evidence shows that taking regular breaks from mental tasks improves productivity and creativity — and that skipping breaks can lead to stress and exhaustion.

I think I’ll go to the gym now.

Mental concentration is similar to a muscle, says John P. Trougakos, an assistant management professor at the University of Toronto Scarborough and the Rotman School of Management. It becomes fatigued after sustained use and needs a rest period before it can recover, he explains — much as a weight lifter needs rest before doing a second round of repetitions at the gym.