A recent study Microsoft conducted in Japan surprisingly revealed that, in one organization at least, moving to a four-day workweek resulted in a 40 percent increase in sales, in addition to saving money in other ways and almost doubling employee satisfaction.

That employees can get more done by working fewer hours seems insane to most businesspeople because we're accustomed to think of human labor as fungible, like money. If you work 100 hours, you get twice as much done than if you work 40 hours.

But the human brain doesn't work like that.

First, labor has diminishing returns. For example: if you're working on a project for 24 hours straight, you're won't as much done during hours 20-24 (when you're tired and burned out) as you did during hours 1-4, when you were energized and fresh.

Second, tired brains make more errors. For example, doctors who work long shifts make an increasing number of mistakes as they approach the end of their shifts. Correcting such errors takes time and costs money--usually more than the value of the extra hours.

So here's the the truth: beyond a certain point (which varies according to the job and the individual) the more you work, the less you get done.

For most people in most work situations, the sweet spot for productivity is between 35 and 45 hours, after which productivity quickly goes negative. Many people--myself and the Microsoft workers included--can get more done in 35 hours than in 50 hours.

If this still seems impossible to you, consider that "the more you work, the less you get done" is much like these time-honored rules of thumb (adapted from a blog post by philosopher Mark Manson):

  • The more you try to impress people, the less impressed they'll be.
  • The more you fear death, the less you'll enjoy life.
  • The more you learn, the more you realize how little you know.
  • The more you try to keep someone close, the further away you'll push them.
  • The more you argue, the less likely that you'll convince others they're wrong.
  • The more choices you have, the harder it is to make a choice.
  • The more convinced you are that you're right, the less likely it is that you actually are.

Accepting these life paradoxes--and that you may be working too hard to be successful--is a surefire recipe for being more productive, more successful, better balanced, and ultimately happier.