The next time you catch yourself lamenting the lack of mystery in modern life, consider how little scientists know about sleep. Why we sleep, not to mention how, remains unknown. Theories abound, of course, especially among those who hope to concoct a better sleeping pill, but the riddle of sleep won't be solved by a new drug. The deeper wonder is how easily most of us slip under without taking a thing. Sleep is a reminder that humans, like all earthly life, are shaped at the deepest level by the whirling of celestial spheres. Sleep also dissolves our sense of self, reducing us each night to what we were before waking to the world. Maybe that explains the unique anguish of insomnia, which cruelly denies its sufferers a brief escape from their own company. Or maybe not. As the following articles suggest, in every age and culture, the mystery of sleep outlives all explanations. —The Editors
I would steal an hour of my lover's sleep if I could. I would slip beneath his eyelids and yank it right out of him. He would feel nothing. Nor would I—neither remorse nor shame. One hour of perfect unconsciousness: one clean, soundless dive, deeper and deeper, as far as my lungs would take me. I would come up for air before he woke. Instead, I lie motionless, sewn to the sheets by the smallest demons, watching Steve's silhouette against the bedroom blinds. Fondness becomes hostility. How does he do this for eight hours? I listen to his tranquil breathing, furious that he sleeps while I cannot.
Finally, at 3 a.m., I snip the threads, discard my carcass at bedside, and leave it behind in disgust. Time for the insomniac to make his rounds. I creep into the next room, where I feel a thrilling freedom from my own body. I am naked, but not cold; not thirsty or hungry; I can smell nothing. My eyesight is shot; I cannot face the TV, work, or read. The plug has been kicked out of the socket, the circadian clock stopped, and I roam the apartment of my own power, on my own theory of time, occupying a fragile space between dreaming and functioning.
A doctor would tell me that sleeplessness in this form may harm, but can never kill. The distinction is far more subtle, as only lifelong insomniacs know: Chronic sleep deprivation transports the body, as through a time warp, into a condition in which it cannot be killed. As much as you might wish for it, the body will neither sleep nor die. By the time I cross this line, the stress and anxiety that first kept me awake are gone. I am beyond the phase of tossing and turning as I worry about a nagging problem—something everyone experiences occasionally. One hour of sleep lost the first night turns into two the next and four the night after. Sleeplessness feeds on itself, reproduces, and quickly becomes the source of apprehension. This severe insomnia visits me at least once a year. I may live with it for weeks—often dozing just two hours per night—before ordinary rest returns.
In my pale, haunted face, I glimpse my father, who felt equally betrayed by sleep's unfaithfulness. If there's such a thing as an insomnia gene, he passed it on to me, along with his green eyes and Irish melancholy. I grew up in a family where the question "How'd you sleep?" was a topic of genuine reflection at the breakfast table. My five sisters and I each rated the last night's particular qualities: when we fell asleep, how often we woke, what we dreamed, if we dreamed. My father's response influenced the family's mood for the day; if it was "lousy," the rest of us were lousy, too.
I often lay awake in bed as a young boy, my mind racing like the spell-check function on a computer, scanning all the data, lighting on images, moments, fragments of conversation, impossible to turn off. As a sleeping aid, I would try to recall my entire life—a straight narrative from first to most recent incident. If my boyhood story didn't lull me to sleep, I'd sneak into the den, where I could find my mother watching Johnny Carson and drinking Coca-Cola, smoking Pall Malls as she folded laundry. After she put me to bed, I would occasionally wander back again, sleepwalking. I would never sit with her, my mother recalls, or respond to her voice. I appeared to be looking for something. I remembered nothing of these night visits. I learned of them at the breakfast table, next morning, where they were the source of laughter from my sisters. This sleep disorder, a "parasomnia" that rarely appears in adults, lasted about a year. In some ways, I find sleepwalking more perplexing than sleeplessness—perhaps because it afflicted me while I was so young, then never returned.
Though I no longer walk in my sleep, I do wander at night, still seeking the peerless soporific. Everybody has a cure to recommend, whether it's warm milk, frisky sex, or melatonin. One friend solemnly prescribes whiffing dirty socks before turning out the lights, but I've found that home remedies are no more effective than aphrodisiacs. Sleeping pills can force the body into unconsciousness, it's true. I've had my jags on Halcion and Xanax, Ambien and Restoril. I've slept many times on those delicious, light-blue pillows. But the body is never really tricked. The difference between drugged and natural sleep eventually reveals itself, like the difference between an affair and true romance.
My lifelong search for sleep has led me to ponder the state in others. You might find me on the subway staring as you come out of nodding off. When people doze in public, the human animal comes out. They burrow into their own clothing or nestle into a friend's shoulder. Undefended from their own small indiscretions, they scratch, grunt, fart, drool, grit their teeth. Sleep also has the uncanny ability both to infantilize and to age, which is especially strange to see in the person with whom you are intimate. After a night of insomnia, I sometimes stand at our bedroom door, coffee in hand, watching Steve sleep. One morning, he's curled up in the fetal position, legs tucked up to his chest, arms hugging a pillow, vulnerable as a baby. With a snort, he rolls onto his back and suddenly he's middle-aged. Another morning, as I hover over him, his sleeping self somehow senses me—and vanishes in a heartbeat. He wakes up, startled, wondering what the hell I'm doing.
Sleep scientists spend their entire waking lives engaged in this kind of surveillance. They may stay up all night just to watch someone awaken. They treat bizarre and dangerous disorders—narcolepsy, obstructive sleep apnea, African sleeping sickness, fatal familial insomnia—as well as the common, everyday sleep disturbances like mine. I've studied the work of modern sleep researchers—along with anatomy, mythology, mental disorders, and aging—hoping to find certain answers my body refuses to divulge. While none of what I've learned has fully unraveled the mystery of sleep, least of all in my own life, I have come to see that sleep itself tells a story.
The ancient Greeks envisioned sleep as the minor god Hypnos, born of night, who lived on the island of Lemnos in a dark cave. Lethe, the river of forgetfulness, flowed through this underworld where Hypnos lay on pillows surrounded by his many sons, including Morpheus, the dream bringer. Unlike his twin brother Thanatos, the god of death, Hypnos was considered a friend of mortals, a healer of body and mind. He took different forms as he wandered the earth—a bird or a child, but most often a benevolent warrior carrying a horn, from which he would drip a sleep elixir. The Greeks apparently took his gifts for granted. No cults arose to worship sleep, which seems odd, for surely there were ancient insomniacs.
Aristotle later saw sleep as the opposite of wakefulness, one of the contraries that "are seen always to present themselves in the same subject . . . health and sickness, beauty and ugliness, strength and weakness, sight and blindness, hearing and deafness." In a sense, Aristotle took the Greek myth and recast it: Now, sleep was the evil twin of wakefulness. "Sleep," he noted, "is evidently a privation of waking." Basing his theory on personal observation rather than prevailing beliefs, Aristotle concluded that sleep was the result of digestive vapors moving up toward the brain. The bigger the meal, the greater the vapors, and the sleepier one got.
Aristotle's ideas remained influential for many centuries. Future experts would try to hunt down the anatomical source of sleep, if only in hope of extending wakefulness. One example—nonsensical in hindsight—can be found in David Hartley's Observations on Man: His Frame, His Duty, and His Expectations, published in 1749. Inquiring into "the intimate and precise nature of sleep," Hartley, an English doctor, stated that sleep could be explained by the "doctrine of vibrations." As Hartley saw it, the body was like a sack of Jell-O—a jiggling mass of solids and fluids that, on occasion, had to come to rest. He elaborated that "during sleep, blood is accumulated in the veins, and particularly in the venal sinuses which surround the brain and spinal marrow; and also, that it is rarefied, at least for the most part."
Hartley and his contemporaries considered sleep necessary but intrinsically bad. Oversleeping (or, heaven forbid, enjoying sleep) demonstrated a character flaw; it was a symptom of sloth and low intelligence. By the 19th century, theories had evolved yet not progressed. Many people believed that sleep was caused by mysterious toxins in the blood. Long popular, the "hypnotoxin" theory suggested that fatigue was a poisonous substance that built up over the day, finally causing sleep at night, when the poison was eliminated.
In a series of experiments in the 1920s, a young Russian-American doctor, Nathaniel Kleitman, first studied the effects of sleep deprivation, disproving the long-held hypnotoxin theory in the process. His research led to two brilliant and simple conclusions. First, people who stayed up all night were more alert in the morning than they'd been in the middle of the sleepless night (as most insomniacs can attest). Second, after about 60 hours of being awake, the ill effects of sleeplessness on a person's health and behavior appeared to level off. Both findings contradicted the belief that fatigue-inducing poisons progressively accumulated in the body.
The hypnotoxin myth was one of many that Kleitman, a University of Chicago physiologist, debunked over a 50-year career. Kleitman, in fact, revolutionized the study of sleep. He established the first clinical sleep laboratory, where he experimented on animal and human subjects, including himself. He made seminal discoveries about the sleep cycle, dreams, sleep deprivation, and sleep disorders. In 1939 he published Sleep and Wakefulness, a classic that remains in print today.
Kleitman is often called the dean of sleep research, yet the image I have of him evokes a very different title. In an enlarged photocopy of a grainy 1938 newspaper photograph that hangs above my desk, he is emerging from Mammoth Cave in Kentucky, where he and an assistant had spent 32 consecutive days as part of a primitive experiment. A tall bearded man in black robes, Kleitman materializes from darkness, followed by a second bearded man, B.H. Richardson, in the same flowing attire. Kleitman's face is bleached as white as the Druidic hood covering his head. Stunned by flashbulbs, he looks like he's been captured against his will. Most details are lost to the inky blackness, yet there's a wild look in his eyes—the look of a man who has been to the underworld and back. It is Hypnos himself, together with Morpheus.
Kleitman and Richardson lived in nearly total darkness, silence, and isolation, seeking nothing less than to challenge the "cosmic forces," as Kleitman put it, that mandate a 24-hour day—that is, the planetary cycle of day and night that dictates when and how long we tend to sleep. They were attempting to adjust to a 28-hour schedule—19 wakeful hours and 9 in bed. Richardson successfully adapted to the 28-hour day, offering proof in Kleitman's mind that cosmic forces were not invincible. His own experience was very different—he slept well only when it coincided with his usual schedule. They both quickly resumed normal 24-hour patterns after they emerged.
Kleitman later attributed his own "resistance to change" (note the hint of self-reproach) to his older age. But the resistance is older than Kleitman, in fact, far older than any of us. Our bodies are little changed from prehistoric times, scientists today believe: timed by the same deeply etched circadian rhythms. The impulse to awaken remains intrinsically linked to the rising of the sun, while dusk stimulates the brain's secretion of the hormone melatonin, inducing a natural drowsiness.
Our entire lives are shaped by such rhythms, gravitational forces, and seasonal cycles: day and night, ebb and flow, growth and decay. In my view, all these patterns may be echoed in grander cosmic schemes. None can truly be resisted, only tested and studied, in Kleitman's cave as in Plato's. Daylight to darkness, the body mimics the behavior of Earth itself. Perhaps this is why vexing sleep questions (Why do humans dream? Why do we wake up?) sound like metaphysical questions about the meaning of life, like excerpts from a timeless dialogue on truth and illusion, awareness and unconsciousness.
Clearly, Kleitman had the soul of an insomniac. In him, I see a mirror image of myself: a man obsessed with sleep, who thinks about it every waking moment, and views his own body as a laboratory for research. I could spend a month in a dark, quiet cave, too. It sounds like being in a perpetual state of bedtime: shut off from the rest of the world, occupied by only another man and a pile of books, and waiting for sleep to come.
These tendencies must begin in utero. Indeed, insomnia may be genetically imprinted at the very moment when sperm meets ovum. Yet sleeplessness cannot exist without sleep itself, embryonic forms of which are not evident until the last trimester of pregnancy. At seven months, scientists can detect brain waves in alternating bursts and hesitations—two to eight seconds each—that suggest the first signs of sleep as we know it. Finally, at eight months, periods of rest and activity—what would be called non-REM and REM sleep in adults—seem to be synchronous with the mother's own sleep cycle. (REM refers to rapid-eye movement, a telltale sign of sleep's active phase, which is associated with dreams.)
I'd like to know the exact moment when the switch is turned on and human sleep begins, or, looking at it the other way, when the switch is turned off. Just as sleep develops, along with organs and limbs, is there also a way in which wakefulness grows? Perhaps driven by this question, scientists at Oxford in the early 1970s performed a series of experiments on pregnant sheep. One of their discoveries was that the sheep fetus seemed to be breathing during periods of rapid electrical brain activity. Although air obviously could not fill the lungs, they speculated that this breathing motion could train the respiratory system for life outside the womb. Taking the first gasp of oxygen might not be possible without it. Previously unknown, the concept of "in-utero breathing" made them wonder if fetuses, animal and human, could be awake during some periods before birth.
The scientists then decided to look in on a fetus—literally. They implanted a clear porthole in the belly of a pregnant sheep, then watched a fetus nuzzling up against the window, like a tiny manatee swimming up to a docked submarine. In what seems an especially cruel prodding, the Oxford scientists later injected the sheep's womb with drugs known to cause waking postnatally. The fetus responded to the chemicals as if they were smelling salts—squirming uncomfortably, breathing rapidly, closed eyes moving—while its brain waves switched to a REM-like state, which suggested that it was dreaming. Its behavior led the scientists to a rather large theoretical leap: In humans, as in animals, REM sleep could be a form of wakefulness. More accurately, it may be a third condition altogether, a cross between the two. Just as in-utero breathing may train the respiratory system, fetal dreams and REM sleep may train the cerebral cortex for life as a functioning human being.
What would one dream in utero? Without visual imagery to draw upon, fetal dreams may be more like dissonant music than a surrealist film: the sounds of maternal organs—heart, lungs, stomach—mixing with speech, laughter, crying. A dream might be choreographed from movements of the mother's body. Or maybe, just maybe, connected as it is by the umbilical cord, the baby has no dreams of its own, but rather dreams what the mother is dreaming.
My mother was dreaming of having a boy, a desire so powerful it may have rubbed off. I was her fifth child in six years, the firstborn son. Delivered by cesarean, as was my sister before me, I can't help wondering if my parents selected my birth date deliberately, as a kind of dual holy day for Irish Catholics like us: January 6, the Feast of the Epiphany, commonly known as the 12th day of Christmas, when the three wise men finally found the manger. I like to think it also observes the term epiphany as redefined by James Joyce: the sudden revelation, by chance word or gesture, of "whatness"—the essential nature of a thing. Eyes open or shut, my life has been a continual, awkward stumbling upon whatnesses, sharp fragments of unexpected meaning. It all started in 1961, around the time I like to get out of bed now, at 8:38 in the morning.
Bill Hayes is writing a book, Sleep Disturbances, to be published by Pocket Books and Washington Square Press. From Speak (Sept./Oct. 1998). Subscriptions: $15/yr. (6 issues) from 301 8th St., Suite 240, San Francisco, CA 94103.