So what's the perfect length for a break? Seventeen minutes, according to an experiment released this week.

DeskTime, a productivity app that tracks employees' computer use, peeked into its data to study the behavior of its most productive workers. The highest-performing 10 percent tended to work for 52 consecutive minutes followed by a 17-minute break. Those 17 minutes were often spent away from the computer, said Julia Gifford at The Muse, by talking a walk, doing exercises, or talking to coworkers.

Telling people to focus for 52 consecutive minutes and then to immediately abandon their desks for exactly 1,020 seconds might strike you as goofy advice. But this isn't the first observational study to show that short breaks correlate with higher productivity. In 1999, Cornell University's Ergonomics Research Laboratory used a computer program to remind workers to take short breaks. The project concluded that "workers receiving the alerts [reminding them to stop working] were 13 percent more accurate on average in their work than coworkers who were not reminded."

It seems unlikely that there is one number representing the ideal amount of time for every employee in every industry to break from work. Rather than set your stop-watch for 17:00 when you get up from your desk, the more important reminder might be to get up, at all. Indeed, the most productive employees don't necessarily work the longest hours. Instead, they take the smartest approach to managing their energy to solve tasks in efficient and creative ways.

Perhaps managing our office energy is a lost art. In the mid-1920s, an executive in Michigan studying the productivity of his factory workers realized that his employees' efficiency was plummeting when they worked too many hours in a day or too many days in a week. He instituted new rules, including an eight-hour work day and a five-day work week. "We know from our experience in changing from six to five days and back again that we can get at least as great production in five days as we can in six," he said. "Just as the eight hour day opened our way to prosperity, so the five day week will open our way to a still greater prosperity."

That company turned out to be one of the most profitable companies of the mid-twentieth century, and the boss at its helm is remembered as one of the most talented executives in American history. His name was Henry Ford.