Tomas Izquierdo has not slept since 1945. Due to an attack of encephalitis,
an inner brain inflammation, his ability to fall asleep was lost at the age of
13. Although he rests with his eyes closed, his brain patterns are those of
someone who is fully awake and aware. He has memory problems and very sensitive
eyes, but is otherwise completely normal. To relax, he usually uses
transcendental meditation from about three or four AM until the morning
(Coleman 94).
Tomas Izquierdo is what one might call someone without circadian rhythms.
Circadian rhythms are the daily sleep patterns of humans. Circadian rhythms
tell people when they are most alert, when they feel tired, and when they
should wake up. These circadian rhythms, while difficult to research, are important
to many industries, as well as a multitude of sleep disorder patients. For
several years, scientists and doctors have been seeking a greater understanding
of these patterns through constant, difficult, and fast paced research. The
applications of such knowledge would be quite beneficial in shift based
industries as well as some special circumstances. As of yet, doctors have been
able to determine a few important correlations between internal time cues and
sleep, activities or events that give cues to the brain about what time it is
or should be. However, the research is very difficult.
Researching sleep is difficult for a variety of reasons. The first reason for
difficulty is the nature of experimentation. To truly isolate the sleep
patterns, all time-giving cues, or zietgebers, have to be eliminated. Light,
electromagnetic waves, the schedules of researchers, and even the growth of a
facial hair on outsiders may lead the subject to guess the time of day. The
body can detect even the faintest cues of time, so it is incredibly important
that the subject be completely shut off from time giving cues. If the subject
of the research knows the time of day, he or she may adjust accordingly,
skewing results and making it all but impossible to collect the data needed.
Another reason for the difficulty of sleep research is the pace of discovery.
The field moves too fast for its own good. As a result, no comprehensive
beginner’s text is available in the field of circadian rhythms. By the time a
book would go to print, too much important experimental evidence would have
been released for it to be considered up to date. So, as of yet, most research
in circadian rhythms remains in the form of scientific newsletters and magazine
articles. While this is a good way for those who are up to date in the field to
stay current, it is all but impossible for an outsider to understand. Due to
this lack of an introductory text, doctors have a more difficult time learning
what has already been proven about sleep (Simon Frasier).
A third difficulty in researching circadian rhythms is the lack of test
subjects. While being paid for sleeping may sound enticing, the reality of
research is much different. People are cut off from contact with their families
and loved ones for months and put in what amounts to a jail cell. The room is
easily compared to the small boxes used by psychologist B.F. Skinner to test
theories of conditioning on mice; not exactly the nicest of conditions to live
in. Subjects are allowed to read old magazines and newspapers, but no current
information is available. If a war were to break out, the subject wouldn’t know
about it until after the study was completed. Live feed-type entertainment such
as radio or television is not allowed. In addition to a lack of freedom and
information, the subjects are tested quite often. For example, take the case of
one such study at the Laboratory of Human Chronophysiology at Montefiore
Hospital. In the study, subjects had small blood samples taken every twenty
minutes, alertness tests about every hour, brainwave monitoring of any sleep,
and continuous rectal temperature readings (Coleman 7). Subjects of any such
research have to be crazy enough to willingly go through this kind of testing
but sane enough to call normal. The experience was described by Preston Keogh,
a subject, in his journal.
“Sometimes I felt like a prisoner, trading my youth for money. Although I
didn’t feel crazy, I thought others might think I was… They took blood samples
every fifteen minutes. I had a catheter in my arm, and a butt probe and all
these things were attached to a movable pole. The first few days there was a
definite presence but after the first week it became a part of you. It was like
having a tail.”
Finding people who are willing to live in these conditions is a major obstacle
to research.
It could be asked, “If it’s so hard to do, why bother with all this research?
What’s so important about sleep patterns?” The importance of sleep pattern
research is threefold. Not only will research in the field of circadian rhythms
help us maximize the alert hours of the general population, but it will also
help to better maximize the schedules of shiftworkers. Shiftworkers are
laborers, usually factory based, that run on a continuous 24 hour schedule,
never stopping. The idea of shiftwork is that expensive or crucial machinery
can be kept operating 24 hours a day. For example, a telephone operator or a
nurse would work on a 24 hour shift system. Sleep pattern research with also
help set the schedules of people in situations where the time-giving cues of
light are not available, such as in spacecraft or submarines. To be able to get
shiftworkers or submarine crews to work more efficiently might mean that less
people and equipment may be needed, possibly saving hundred of thousands of
dollars. The first step in this research is defining a normal sleep pattern.
Research has defined a “normal” sleep pattern for adults. Studies have been
done all over the world in the field to describe what is considered normal among
adults. In one such study sponsored by Stanford University, three rooms of a
hospital were sectioned off for testing. The center room was used as a control
room, and the other two rooms were used as bedrooms for test subjects. The test
subjects were instructed to stay in the rooms, which had no windows or clocks,
and sleep on a regimented schedule for twenty days. After the twenty days
passed, they were told to sleep whenever they wanted to. The scientists asked
that they take only one sleep period a day. Volunteers had no contact with the
outside world other than the staff. The staff, of course, was instructed to
remove any trace of a sense of time from their habits. They had to remove all
wristwatches, use time-neutral phrases like “hello” instead of “good morning,”
and shave just before handling test subjects. Their work schedules were
determined randomly by computer. Even with all of these precautions, the test
subjects mostly followed identical patterns of sleep. These somewhat identical
sleep patterns were therefore dubbed “normal” and taken as natural (Coleman 6).
Normal sleep patterns include a few main ideas. First, most adults sleep for
about eight hours each day. If asked to sleep less, most can function at the
same level of efficiency with less sleep. In fact, after eight weeks of
sleeping for five and a half hours a night, most subjects report that they no
longer felt drowsy during the day. However, these sleep deprivation studies
have shown that even after months of sleeping four or five hours a night,
people go back to the eight hour standard citing that they just feel better
when they get more sleep (Coleman 98).
In addition to an eight hour sleep period, normal sleep patterns include free
running. Free running is the practice of going to sleep one hour later than the
night before. In the aforementioned Stanford study, most subjects were found to
fall asleep an hour after they would have the night before. Scientists believe
that this phenomenon, called free running, is due to a natural 25 hour cycle
that humans run on. In the absense of time cues, 25 hours seems to be the
preferred length of day for the average adult (Coleman 8).
Beyond the 25 hour cycle, scientists know bits and pieces of other information.
For example, scientists know a small amount about alertness levels. Alertness
levels are highest during the middle of the day, and lowest during the first
hour before and after sleep. After a sleepless night, a normal person will
return to higher alertness on the cue of light. So, if a person were to stay up
all night intentionally, they would feel somewhat refreshed in the morning,
even without sleep. This feeling, of course, lessens over repetition, so sleep
cannot be abandoned altogether. Now that scientists know some of the basics of
normal sleep patterns, the next step in research is correlating between time
cues and those sleep patterns (Coleman 20).
Currently, research shows several correlations between certain time cues and
circadian rhythms. One such time cue is light. For example, people in subarctic
climates often have very long or very short days. During winter it can stay
dark for all 24 hours of the day. As a result, some people suffer from SAD, or
Seasonal Affective Disorder. Those with SAD have symptoms of depression, increased
weight, and, perhaps most importantly, sleepiness. According to Richard
Coleman, the disorder is related to the secretion of melatonin, a hormone that
is released from the pineal gland during the night. The body senses that it is
dark, and then responds by secreting melatonin. Those with the disorder
actually suffer from an overdose of melatonin due to the lack of daylight. By
not getting enough sunlight, their bodies over-secrete melatonin, causing the
symptoms above. By having the patient sit in front of a light for three to five
hours, doctors have reduced the amount of depression and sleepiness in many
cases by simulating a 13 hour light cycle. This 13 hour light cycle is very
similar to the light cycle of those found in warmer climates, and is much more
beneficial to those with SAD.
It may seem odd that the body could unconsciously identify the availability of
light, deciding when to be alert and when not to be based on the presence of
light or lack thereof. However, such light-sensing can be physiologically
explained. Last April, Dutch and Japanese scientists studied mice without
normal rods and cones in their eyes. Rods and cones are the light and color
sensing structures of the retina that allow animals the sense of vision. Their
research indicated that the mice could still reset their circadian clocks, even
without the help of these light sensing structures. So, in effect, the blind
mice could tell when there was light and when there wasn’t. Their conclusion
was that there had to be another structure within the eye that senses light for
the purpose of circadian rhythm regulation. The importance of this conclusion
is that if scientists could isolate and study the structure, then they could
better diagnose and treat SAD as well as a variety of sleep disorders
(Circadian).
Another physiological reason for the regulation of circadian rhythms is the
presence of Cryptochrome, or CRY, an eye pigment protein found in mammals. In a
study at the University of North Carolina, two individual types of CRY were found
to cause changes in the speed of the biological clock. They were named CRY 1
and CRY 2. (Discovery). In mice, CRY 1 deficiencies sped up the biological
clock, while CRY 2 deficiencies slowed it down. (Circadian) So, in effect,
scientists have located the tools to adjust the circadian rhythms of just about
any mammal. However, the location of the tools is not important unless they can
be used.
Geneticists working on the human genome project have already located and
identified the genes responsible for the production of the pigments. The human
genome project is the project to map an entire DNA strand systematically and
know what each part of the strand does. Using this gene technology, scientists
have spliced the DNA of humans together with that of bacteria to produce
artificial bodily substances like insulin. This artificial insulin is the same
as human insulin in every way, except for the fact that it was made by
bacteria. Scientists may some day be able to use their knowledge of these CRY
pigment genes to produce an artificial supplement, somewhat akin to artificial
insulin. Such a drug would provide a more natural way of regulating the sleep
cycles of narcoleptics, insomniacs, and many other sleep disorder patients.
Another important correlation that scientists have found is age. The elderly
are often the most restless of all the people in our society, taking less hours
of sleep than anyone else. 40% of all sleeping medications are prescribed for
the elderly. As humans age, a part of their brain known as the suprachiasmatic
nucleus, or SCN, gets smaller. The SCN is the primary pacemaker for most
circadian functions in the brain. It is responsible for the production of the
sleep hormone melatonin. As the SCN decreases in size, less melatonin is
produced, causing a shift in sleep patterns. The drop in melatonin, just as in
SAD patients, can cause restlessness. In order to counteract this melatonin
loss, many of the elderly sit in front of light boxes, just like the SAD
patients, at the end of the day for a few hours (Center for Biological).
Circadian rhythms are part of the daily lives of humans. They cue our levels of
alertness, our need for sleep, and our time of waking. To better understand
these rhythms, scientists from around the globe have participated in difficult
research for years. As of yet, the research shows that light, hormones,
exercise, age, and a variety of other factors are important in determining
circadian rhythms. Perhaps in the future, scientists will be able to manipulate
circadian rhythms so that people no longer feel fatigue. By then, maybe Tomas
Izquierdo could finally get some long overdue sleep.