As reported by The Hartford Courant, January 1, 2006.

Sleep: Part One

The Enigma of Sleep

A good laugh and a long sleep are the best cures in the doctor’s book.

By Matt Eagan

There are few biological imperatives more urgent than sleep, but eons after early humans spent that first night in the back of a cave, much of what happens when we slumber remains a mystery.

For centuries, from Aristotle to Thomas Edison, people have pondered the meaning of sleep and offered bits of wisdom about its purpose.

Almost all were wrong.

About 50 years ago, the study of sleep entered a more sophisticated age, and doctors were able to break down the various stages of sleep - including REM (rapid eye movement) sleep necessary for dreaming - but answers to more basic questions have proved elusive.

"There is lots of controversy about - why sleep?" says Dr. Daniel McNally, director of the sleep disorder center at the University of Connecticut Health Center. "What is it? People have looked over a long period of time to say, `Can I find a substance that the body eliminates? Can I find a substance the body rebuilds? Can I find something it stocks up on - and it's actually very, very hard to show that."

Hints about why sleep is necessary can be found in the behavior of those who do not sleep enough.

Given any excuse, Americans will skip their slumber to watch sporting events that finish in the bleary-eyed hours of the morning or to see a few jokes from David Letterman's monologue.

A recent National Sleep Foundation study found that Americans average about 6.8 hours of sleep each weeknight, short of the minimum seven hours recommended.

Edison said sleep was a waste of time. He was wrong.

Nearly all doctors who study sleep conclude the same thing - it is a stubborn foe, an enforcer that intrudes upon our waking hours.

Consider the Abbott and Costello routine, in which they agree to split shifts on a watch.

Abbott sleeps first.

When it comes his time to watch, he simply sets the clock ahead and wakes Costello, whose head has barely touched the pillow.

This happens again and again. By the end of the night, Costello is at his babbling, incoherent best and he can't stay awake.

Funny. Accurate.

"The main consequence of not sleeping is you become more sleepy," McNally says. "Sleep intrudes."

At a basic level we know why this happens. Sleepiness is the body's attempt to enforce a circadian rhythm. Even bacteria, in a very crude sense, can tell time by distinguishing light from dark. When the amount of light available is altered, bacteria will change their metabolism.

This rhythm also applies to our own cells, which is another way to say that our own bodies follow the sun and rebel against our attempts to remain awake without it.

This ancient rhythm is among our most powerful biological compulsions.

Some argue that, in a Darwinian sense, sleeps seems a foolhardy endeavor, especially for early humans, who were surrounded by predators and had few natural defenses.

Others say it makes a certain sense to hide in a cave at night when saber-tooth tigers roamed the countryside looking for snacks.

Whatever its Darwinian purpose, there is no doubt about the strength of the sleep drive.

Consider other drives, such as the need for food or sex, which each have their own cable channels.

People can go days without food and a lifetime without sex, but sleep will intrude on them after about 24 hours.

Studies have shown that people assigned a simple task - pressing a button every time they hear a bell - will stop performing the task if deprived of sleep.

Their brain waves will reveal that they were asleep, even as they insist that they have remained awake the entire time. This is sleep, the enforcer.

"If you can't sleep, then get up and do something instead of lying there worrying. It's the worry that gets you, not the lack of sleep," Dale Carnegie, perhaps the nation's first self-help guru, once said.

Carnegie was wrong.

There is medical debate about whether someone denied sleep would eventually die (most suggest he or she would), but there is no doubt that a lack of sleep can, in fact, get you.

"There are a lot of changes in people who don't sleep," McNally says. "Their immune defenses, their body chemistry, things related to their blood pressure, how their bowels function. Our biological systems are tied together and when people are deprived of sleep, it causes changes in their immune defenses that put them at more risk."

Doctors also say regular sleep can improve our memory, our job performance, help us lose weight (by changing metabolism) and fight off a host of airborne maladies.

There may be other benefits, but sleep is hard to study, precisely because it is so necessary. Doctors are reluctant, for obvious ethical reasons, to conduct studies where people are denied sleep because it's hard on their bodies and minds.

About 2,350 years ago, Aristotle concluded that sleep was how we let our brains cool.

Aristotle was wrong.

Although the body seems inactive during sleep, our brains are cooking.

During sleep, the brain begins its housecleaning, taking immediate memories and turning them into short-term memories and taking those things stored in short-term memory and moving them into the warehouse of long-term memory.

Change the way we sleep, and it changes the way we store facts and figures from the previous day and alters our perception of what we have learned.

Put another way, short-changing on sleep can make you dumber.

And any old sleep will not do. Those seeking to catch a few hours on a plane or a train will not overcome a sleep deficit that occurs when we spend fewer than seven hours a night in our own comfy beds.

"Quality is a key," says Dr. Robert Bundy, medical director of the Eastern Connecticut Sleep Program at Windham Hospital. "As adults we desire a consolidated, comfortable sleep for eight hours. If you don't get it you will start to see it take a toll."