So this explains the nation's surging labor productivity — in 2003, just 21 percent of employers allow power-napping on the job, down from 44 percent in 2002 and 48 percent in 2001, according to an article in The Wall Street Journal.

But is the gain short-lived? A quick cat nap, in the vicinity of 15 to 20 minutes (no more than 25), will maximize productivity and mental acuity, says Betsy Connolly of Circadian Technologies. Naps longer than 20-25 minutes cause a person to go into such a deep sleep that he or she will be groggy when awakening. Despite the perception by management that those who nap on the job are slackers, perhaps nappers are actually the most productive, she says.