The Dream Sourcebook: A Guide to the Theory and Interpretation of Dreams (6 page)

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Authors: Phyllis R. Koch-Sheras

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BOOK: The Dream Sourcebook: A Guide to the Theory and Interpretation of Dreams
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dreaming that have nothing to do with unresolved conflicts or hidden meanings. Chapter 3 offers an overview of the many theories that form the basis of current dream thought.
"He Died in His Sleep"
Have you ever stopped to wonder just why people die in their sleep? As early as the 1920s, one doctor guessed that there might be a correlation between the sleep "disturbances" we now know to be REM sleep and the incidence of heart attack. We know today that most heart attacks during sleep occur in the early morning hours, when the longest period of REM sleep takes place. Given that heart and breathing rates increase and become more erratic during REM sleep, sometimes reaching levels not seen during waking life, it makes sense that a diseased heart might one night fail to withstand the strain. No one knows for sure whether dream content or emotion plays a role in nighttime heart attack, or to what extent the heart attack is merely the result of the high physical demands of the REM period.
The Mechanics of Dreaming
Your adrenaline is racing. Your blood pressure increases as your heart beats faster and faster. Your breathing becomes rapid and shallow. The final leg of a challenging foot race? Far from it. Would you believe this is the description of your sleeping body during the dreaming stage? It's true. A 1993 study at
 
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the University of Iowa found that the human body's dreaming condition is much like the fight-or-flight response in waking life, which gears the body up to confront a threatening situation. Yet your brain simultaneously signals your spinal cord to hold your body completely still. Science is still trying to determine exactly what physical function dreaming has for us, but since the 1950s, researchers have made remarkable advances in the study of sleep.
In centuries past, most people saw sleep as a kind of unconscious state or temporary death. The child's bedtime prayer may be a reference to the idea that the soul temporarily leaves the body: "Now I lay me down to sleep/I pray the Lord my soul to keep/If I should die before I wake/I pray the Lord my soul to take." But today we know that sleep is not merely a seven- or eight-hour period of total unconsciousness. You may be "dead to the world," but your mind is very much alive, cycling through periods of intense activity and periods of rest. The cycles of sleep are a fairly new discovery, but in the years since researchers finally cracked the code of sleep we have learned a great deal about what our bodies do when we dream. We now know that sleep is made up of a pattern that alternates between a stage in which brain activity heightens and dreaming takes place and a stage of "quiet sleep,'' so called because you are generally sleeping without much disturbance, still and relaxed, without the rapid eye movement and accompanying brain waves that indicate dreaming.
You've probably heard of REM sleep, which is the particular stage of sleep we're in when we dream. The term
REM
stands for rapid eye movement, and this stage is so called because the eyes move back and forth beneath the eyelids, as though they are watching an action-packed movie. Observe someone sleeping sometime and you'll see how the eyelids seem to flutter as the eyes roll beneath them; if you are able to wake
 
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the person up during REM, chances are that he or she will be able to recall a dream, even if usually unable to do so after waking up in the morning. Awaken that person during non-REM, or quiet sleep, and he or she will be hard-pressed to recount any dream activity at all.
The discovery of rapid eye movement is legendary. In the early 1950s, in the University of Chicago laboratory of sleep researcher Nathaniel Kleitman, a graduate student named Eugene Asirinsky sat monitoring the staggering pen marks of an electroencephalograph (EEG) machine. The EEG machine's wires led to electrodes attached to an infant, whose brain waves were Asirinsky's focus of interest. The story goes that Asirinsky thought the machine was broken when the graph in front of him suddenly began to stagger wildly. After all, sleep was a period of rest. Only after checking the connecting wires did he discover the baby's rolling eyes. What could it mean?
Kleitman and Asirinsky, working together with medical student William C. Dement, began to research whether adults had these same eye movements during sleep. Awakening their research subjects during REM sleep led them to conclude in 1953 that REM sleep takes place only during the dream stage; subjects roused during REM sleep were far better able to describe their dreams in vivid detail than those who slept through the night or were awakened during what came to be known as non-REM sleep. As Dement recalls in his book
Some Must Watch While Some Must Sleep
, "This was the breakthroughthe discovery that changed the course of sleep research from a relatively pedestrian inquiry into an intensely exciting endeavor pursued with great determination in laboratories and clinics all over the world."
The discovery of REM sleep led to other related conclusions about sleep and dreams. Whereas previous researchers had taken random EEG readings, Dement studied the entire night's
 
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sleep in several subjects over several days. This research allowed him to document regular periods of dreaming and sleeping. In this way, he was able to put to rest the notion that dreams occurred randomly as a result of indigestion, environmental noise, and other circumstances. Although scientists still couldn't say for sure why dreams occurred or where they came from, they were at least able to determine when they occurred and what things did not cause them.
The Sleep Cycle
Thanks to these dream research pioneers, we now know that there is a regular cycle of sleeping and dreaming during each period of sleep. For most of us, a night of sleep begins with the usual rituals: checking to see if the front door is locked, turning out the lights, brushing the teeth, washing the facewhatever we have become accustomed to doing night after night. We change or remove our clothes. We get into bed, usually on the same side. Then it's lights out, and we lie in wait for the magic calm of sleep to overtake us.
Sleep comes in an instant: One second you are awake, the next you are asleep. Here's what happens in the minutes preceding that fateful second in which you drop off. First, your body temperature drops. Your eyes close, and your brain waves begin regular alpha rhythms, indicating a relaxed state. Soon, Stage One sleep begins, as your muscles lose their tension, your breathing becomes more even, and your heart rate slows. A few minutes later, Stage Two sleep begins, and random or nonsensical images may float through your mind, mimicking the dream state. Occasionally, you may become alert enough to interrupt these hypnogogic dreams, or dreamlets. Resistance to falling asleep sometimes registers in these snippetsthe myoclonic jerk,
 
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for example, that jolts you back to wakefulness, or the occasional involuntary movement or twitching you sometimes see in both humans and animals.
In time, you'll float on into Stage Three sleep. Your body continues its slowdown process: Muscles lose all tightness, breaths come slowly and rhythmically, heart rate decreases, blood pressure falls. At this point, it would take a loud noise or other disturbance to pull you from your slumber. You are fully asleep.
Think of Stage Four sleep as deep sleep. If you do awaken from this type of sleep, you may well feel "fuzzy" or disoriented for a few minutes. Stage Four is considered to be the most physically restful period of sleep, and it is the longest in duration.
Where does dreaming fit in? Think of Stages One through Four as a cycle (see page 19). After about an hour and a half of moving through these stages, you cycle back through Stage One to resume Stage Two sleep, a lighter sleep in which your brain is more active. Indeed, brain waves show a great deal of activity. And here is where rapid eye movement begins. Surprisingly, studies show that it can be more difficult to awaken a sleeper during this lighter phase of sleep than any other. The body at this stage seems poised for "fight or flight." Remember how your heart and lungs seemed determined to put you into cold storage for the night? Your heart is slow and regular, your breathing deep and even. Then REM sleep takes you right out again. Your heart rate may fluctuate wildly, your breathing becomes irregular and fast. In fact, your breathing may become so shallow that, if you were awake, you would feel as if you were holding your breath, and might have to stop any second.
It is during this phase, which lasts from ten to sixty minutes each time, that dreams take place. Everyone has from five to seven dreams during a normal night's sleep, with each dream lasting from a few seconds to as much as an hour. These dreams
 
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do not occur in a flash; in fact, the perceived duration approximates the actual time spent dreaming. As each REM period ends, your body cycles back through Stages One through Four every ninety minutes until you awaken.
Body Drnamics
The body goes through some interesting changes during the REM stage of the sleep cycle. Rapid eye movement is perhaps the most intriguing of these. Why do our eyes move back and forth as though we are watching a movie? Are we looking at imagined images? Yes and no. Studies show dreamers' eye movements do seem to coordinate with the action they see on their dream screens. Yet even those who have been blind from birth have rapid eye movement during Stage One sleep.
Despite the hyperactivity of the eyes, the body goes from a relaxed and almost motionless state during other stages of sleep to a fairly rigid position during REM sleep. Sure, hands and feet may jerk and twitch, and the face may register some expression or movement, but any instructions the brain might send to the muscles to move go straight to the dead-letter office, stuck in the spinal cord. Although a person generally moves during sleep, a
dreaming
person is incapable of moving during the REM periodat least voluntarily. (Contrary to popular belief, sleepwalking does not occur during the dream state.) Involuntary twitching or jerking may occur, however.
There are other physical characteristics of dreaming as well. In adults and infants alike, the head and chin relax so completely that researchers can use the slackening of the muscles under the chin as a reliable signal that REM sleep is occurring. This phenomenon is not just restricted to humans; in rabbits, for example, the ears remain straight back on the head for all stages of
 
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sleep. But when the rabbit starts to dream, the ears flop down on either side. Other animals, such as dogs, cats, rats, and monkeys, exhibit the same type of twitching, rapid breathing, and even penile erections during their dreams. And REM sleep patterns have been detected in every mammal investigated, as well as in birds.
A human male of any age (even infancy) will experience an erection at the beginning of each REM periodeven when his dreams contain no sexual content whatsoever. These erections occur about every eighty-five minutes, just before REM begins, and last about twenty-five minutes. Does this timetable sound familiar? It's roughly the same as the REM portion of the sleep cycle. Why it happens is a mystery, but given that it happens even when a dream has no sexual content, it may have to do with the overall stimulation of the nervous system.
Mood-Altering Substances and Dreams
Though spicy foods and heavy meals late at night have been proven to have no effect on our dreams, there are certain substances that impact our REM sleep, for better or worse. For example, Anthony Sifton reports in
The Dream Reader
(1995) that "marijuana and cocaine both decrease dream recall." Barbiturate use, he reports, leads to "more conceptual and thoughtlike" dreams. Alcohol, tobacco, and stimulants such as amphetamines ''generally reduce REM time. So do barbiturates, benzodiazepines [such as Valium and Xanax], and most of the sedative-hypnotic sleeping pills, tranquilizers, muscle relaxants, etc." Interestingly, caffeine does not affect REM sleepunless you are attempting to withdraw from it, in which case you will begin to dream more. "That is the effect of withdrawal from any stimulant," Sifton writes, noting that it is unclear whether stress is a factor in increasing the number of dreams.

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