His group has also found benefits in the "prophylactic" nap for people who have to stay up late. "It protected them from sleepiness," he says. "A two-hour or a four-hour nap, before they have to be up all night, does provide additional alertness the next day." Research conducted by NASA produced similar results.
Naps are clearly useful for some people, including shift workers, students, and anyone doing long-haul work, such as pilots on transcontinental runs.
But afternoon sleep won't benefit everyone, especially people suffering from insomnia or depression, says Michael Perlis, Ph.D., Assistant Director of the University of Rochester Sleep Research Laboratory. "In the case of the former, napping may worsen nocturnal sleep in patients with insomnia," he says. "As for the latter, napping may increase depressive symptoms."
Sleep researchers agree that anyone who wants to benefit from a nap should make sure not to lie down too close to bedtime or sleep for more than 90 minutes. Doing so can throw off the circadian rhythm -- the body's internal clock.
The How-To of Napping
Anthony's personal rhythm now includes his afternoon nap. He falls asleep easily -- despite the loud rattle of the Boston's "T" trolley, which runs right past his office -- and wakes up automatically after 20 minutes.
Along with his wife, Camille, Anthony has written two lighthearted "Art of Napping" books, sells napping equipment on a web site, and makes the rounds of the morning talk shows.
His latest campaign is to promote workplace napping. On his web site he sells little signs to hang on your office doorknob that read "Working Nap in Progress."
"Most Americans are sleep deprived," he says. "They're having accidents, they're not being as productive as they could be, and they're being interpersonal dolts -- all because they are sleepy."
In his book, he offers tips on how to sleep at work, something most employers discourage. But Anthony profiles the Pittsburgh office of Delloite Consulting and a Connecticut metals distributor, which offer workers a nap room.
The bottom line, he says: "There is something to be said for getting horizontal."