First, turn off the alarm clock. It isn't doing a thing for the biological clock you were born with, the one that sets all the rhythms of your body, sets your natural cycles of wakefulness and energy, and dictates the daily fluctuations of body temperature and hormone production that influence your physical and psychological state.

In fact, if you need an alarm clock to wake you up in the first place, that's a sure sign you aren't getting enough sleep. If you allowed yourself to go to sleep when you are tired, and trusted your body to gauge its own need for sleep, you would be able to wake up without an alarm clock. And you'd feel energized the whole day.

Short of that, you are building up a sleep debt, a debt that doesn't dissipate with time but only gets compounded. Some experts claim we are so sleep-deprived we are deluded into thinking we are functioning just fine, all the while sleep deprivation affects our mood, our performance, and our behavior. We make excuses for our drowsiness—the room is too warm, the speaker is too boring—when the true cause is chronic shortage of sleep.

The problem isn't just that we are busy. Somewhere along the line we stopped valuing sleep. We have come to think of it as wasted time and we do our best to dispense with it. In the past century, we have reduced our average time asleep by 20%. By contrast, in the last quarter century alone we added a month to our annual work/commute time.

Sleep makes us feel guilty, as if by sleeping we are deliberately handing over to the next guy the opportunity to beat us at our own game. I'm sure you read the same newspaper and magazine profiles that I do; stories abound about successful executives arriving at the office at 5 a.m. The implication is clear. We're letting the hours slip by in bed while they are busy doing. Early birds catch the worms, don't they?

There is a kind of poetic justice to the fact that as I write these very words my computer clock reads precisely 3:08 a.m.—that's three in the morning. Despite being tired I couldn't fall asleep. I read as much of the new issue of The New Yorker as I wanted; the only thing left to do was get out of bed and write. I was anxious about all the work I had to do anyway, so I decided to tackle the issue head-on. So what if it's now 3:10 in the morning.

I'm not sure where our collective sleep guilt is coming from. I'm sure our Puritan heritage contributes something, a sense that sleeping is a sign of laziness, and laziness is ungodly. We are born to work, not to loll in bed.

Sometime over the past decade or two we slipped into the 24-hour society. Financial markets around the globe, the internet, portable telephones... there is always work to be done and it beckons around the clock.

But the news from the laboratory is compelling. Sleeping is anything but loafing. Even 10-hour sleepfests are sometimes required for the body to get on track. And according to some research, 10 hours of sleep a night are required for preparing the body and mind for optimal performance. We regard eight hours of sleep as a luxury, but 10 hours are the amount people often sleep in nonindustrialized cultures, the amount that is natural for us.

What I think our sleep guilt has to do with is that we no longer trust the wisdom of the body. Take, for example, the case of dieting. Decades of dieting—and who among us hasn't dieted?—have destroyed our inborn sensitivity to the body's own signals of hunger and satiety. We have overridden them for so long we no longer heed them—or even recognize them. We come to doubt that they exist. At the very least, we grow to mistrust the wisdom of the body, for it has betrayed us by presenting the need to diet in the first place.

So it is with sleep. We have been overriding body signals of sleepiness and wakefulness for so long now that we have grown to doubt their value to our needs, and to mistrust them. Instead we set our body clocks to oscillate between the twin poles of caffeine and sleeping pills. Our disobedience to the body's need for sleep typically starts in college—and continues thereafter.

But the body has a wisdom. And maybe we'd all be a little happier, a lot less irritable and better able to concentrate if we just slept a little more.

As for me, I'm going to bed. It's 3:56 a.m.