If you're working harder and putting in longer hours, and you're still struggling to get everything done, Tony Schwartz has a message for you.

You can get more work done by devoting more time to doing less.

"A new and growing body of multidisciplinary research shows that strategic renewal — including daytime workouts, short afternoon naps, longer sleep hours, more time away from the office and longer, more frequent vacations — boosts productivity, job performance and, of course, health," Schwartz writes in a Feb. 9 piece for the New York Times.

Schwartz, a former journalist who founded a corporate-advisory firm called the Energy Project, asserts that productivity is a function of energy management, not time management.

"Time is the resource on which we've relied to get more accomplished," Schwartz writes in his New York Times piece. "When there's more to do, we invest more hours. But time is finite, and many of us feel we're running out, that we're investing as many hours as we can while trying to retain some semblance of a life outside work.

"Although many of us can't increase the working hours in the day, we can measurably increase our energy."

While most of us in the business and manufacturing world push harder when our work demands ratchet up, Schwartz notes that athletes are among those who understand that "the greater the performance demand, the greater the need for renewal."

"The importance of restoration is rooted in our physiology," Schwartz writes. "Human beings aren't designed to expend energy continuously. Rather, we're meant to pulse between spending and recovering energy."

Working in 90-Minute Intervals

In addition to advocating for more sleep and longer vacations, Schwartz asserts that working in 90-minute intervals is the best way to maximize productivity during the workday.

He bases that assertion on research conducted in the 1950s that concluded that human beings sleep in 90-minute cycles, alternating between light and deep sleep.

Likewise, "during the day we move from a state of alertness progressively into physiological fatigue approximately every 90 minutes," he says.  

"Our bodies regularly tell us to take a break, but we often override these signals and instead stoke ourselves up with caffeine, sugar and our own emergency reserves — the stress hormones adrenaline, noradrenaline and cortisol," Schwartz writes.

Schwartz cites research by Florida State University professor K. Anders Ericsson, who found that top musicians, athletes, actors and chess players "typically practice in uninterrupted sessions that last no more than 90 minutes."

"They begin in the morning, take a break between sessions, and rarely work for more than four and a half hours in any given day," Schwartz adds.

Schwartz says he puts these principles into practice at his own firm, which subscribes to the notion that "the energy employees bring to their jobs is far more important in terms of the value of their work than is the number of hours they work."

"In a decade, no one has ever chosen to leave the company."