Nap attack!

One of the great tragedies of modern life:

I love to nap. When after-lunch grogginess hits and my eyelids start to droop, nothing makes me happier than finding a comfortable spot and drifting off to sleep for half an hour.

But to my wife, my napping is the sign of a basic character flaw.

"You're napping again? I can't believe how lazy you are!"

She's not alone. To be an enthusiastic napper in 21st-century North America is to be out of step with your time and place. In most of the industrialized world, a nap is seen as a sign of weakness, either physical or moral. The very young and the very old nap. Sick people nap.

Count me among the nap lovers (which can be as little as 10 or 15 minutes and as much as an hour; anything longer, and we are talking lazy bum). I usually find that, with a little nap, I can work 10 hours in a day and feel less tired than working a regular 8-hour day without the nap. And, of course, I love my snooze alarm, which is the equivalent of several naps before even getting out of bed in the morning. And it turns out that naps might have science on their side.

As a species, we seem designed to nap. Sleep researchers have long known that our natural circadian rhythms show two distinct dips in energy and alertness. The major dip starts in the late evening, helping us get ready for a good night's sleep.

But there's another significant dip in the early afternoon that, in a saner world, would have us all dropping off. From an evolutionary point of view, this pattern makes some sense — our ancestors evolved in the tropics, where a desire to sleep during the hottest part of the day probably helped ensure survival.

Sleep researcher Claudio Stampi, founder of the Chronobiology Research Institute in Boston, thinks the tendency to nap might have an even deeper meaning. It could be the remnant of ancient "polyphasic sleep" — a sleep pattern with no long nighttime sleep but lots of short naps throughout the day and night. Many animals sleep this way, as well as newborn babies. If Stampi is right, there was a time when our pre-human ancestors slept only in naps.