Be smarter at work, slack off, money.cnn.com :]

Remember the story of Archimedes lolling in his bathtub? To an observer, he'd have seemed to be wasting time. While ostensibly doing nothing, however, he discovered the principle of displacement, a cornerstone of physics. Would he have reached the same insight in a quick shower? Unlikely. And while you might say that's ancient history, don't be too sure.

Consider that for most industries, the U.S. can't hope to be the low-cost producer in a global economy. With innovation now our main competitive strength, creativity is crucial for anyone who wants to move up. But it's really, really hard, if not impossible, for the human brain to come up with fresh new ideas when its owner is overworked, overtired, and stressed out. And in today's wonderful world of nonstop work, 40% of American adults get less than seven hours of sleep on weeknights.

"The physiological effects of tiredness are well-known. You can turn a smart person into an idiot just by overworking him," notes Peter Capelli, a professor of management at Wharton. Still, putting in more than 50 hours a week at the office has become routine -- and that doesn't count time spent doing paperwork at home, answering e-mail at the airport, or talking on the phone in the car. Sooner or later, companies' performance has to reflect that, Capelli says. "On the organizational level, what you get is, everyone is so focused on running flat-out to meet current goals that the whole company is unable to step back and think."

So it could well be that, in the era of knowledge work, the most prosperous companies will turn out to be those that encourage people to build some slack into their days.