Do you ever feel sleepy or “zone out”
during the day? Do you find it hard to wake up on Monday mornings?
If so, you are familiar with the powerful need for sleep. However,
you may not realize that sleep is as essential for your well-being
as food and water.
Until
the 1950s, most people thought of sleep as a passive, dormant part of
our daily lives. We now know that our brains are very active during
sleep. Moreover, sleep affects our daily functioning and our physical
and mental health in many ways that we are just beginning to understand.
Nerve-signaling
chemicals called neurotransmitters control whether we are asleep
or awake by acting on different groups of nerve cells, or neurons, in
the brain. Neurons in the brainstem, which connects the brain with the
spinal cord, produce neurotransmitters such as serotonin and
norepinephrine that keep some parts of the brain active while we are
awake. Other neurons at the base of the brain begin signaling when we
fall asleep. These neurons appear to “switch off” the signals
that keep us awake. Research also suggests that a chemical called
adenosine builds up in our blood while we are awake and causes
drowsiness. This chemical gradually breaks down while we sleep.
During sleep, we usually pass through five phases of
sleep: stages 1, 2, 3, 4, and REM (rapid eye movement) sleep.
These stages progress in a cycle from stage 1 to REM sleep, then the
cycle starts over again with stage 1 (seefigure
1). We spend almost 50 percent of our total sleep time in stage
2 sleep, about 20 percent in REM sleep, and the remaining 30 percent
in the other stages. Infants, by contrast, spend about half of their
sleep time in REM sleep.
During
stage 1, which is light sleep, we drift in and out of sleep and can be
awakened easily. Our eyes move very slowly and muscle activity slows.
People awakened from stage 1 sleep often remember fragmented visual
images. Many also experience sudden muscle contractions called hypnic
myoclonia, often preceded by a sensation of starting to fall. These
sudden movements are similar to the “jump” we make when
startled. When we enter stage 2 sleep, our eye movements stop and our
brain waves (fluctuations of electrical activity that can be measured by
electrodes) become slower, with occasional bursts of rapid waves called sleep
spindles. In stage 3, extremely slow brain waves called delta
waves begin to appear, interspersed with smaller, faster waves. By
stage 4, the brain produces delta waves almost exclusively. It is very
difficult to wake someone during stages 3 and 4, which together are
called deep sleep. There is no eye movement or muscle activity.
People awakened during deep sleep do not adjust immediately and often
feel groggy and disoriented for several minutes after they wake up. Some
children experience bedwetting, night terrors, or sleepwalking during
deep sleep.
When we switch into REM sleep, our breathing becomes
more rapid, irregular, and shallow, our eyes jerk rapidly in various
directions, and our limb muscles become temporarily paralyzed. Our
heart rate increases, our blood pressure rises, and males develop
penile erections. When people awaken during REM sleep, they often
describe bizarre and illogical tales — dreams.
The
first REM sleep period usually occurs about 70 to 90 minutes after we
fall asleep. A complete sleep cycle takes 90 to 110 minutes on average.
The first sleep cycles each night contain relatively short REM periods
and long periods of deep sleep. As the night progresses, REM sleep
periods increase in length while deep sleep decreases. By morning,
people spend nearly all their sleep time in stages 1, 2, and REM.
People
awakened after sleeping more than a few minutes are usually unable to
recall the last few minutes before they fell asleep. This sleep-related
form of amnesia is the reason people often forget telephone calls or
conversations they've had in the middle of the night. It also explains
why we often do not remember our alarms ringing in the morning if we go
right back to sleep after turning them off.
Since
sleep and wakefulness are influenced by different neurotransmitter
signals in the brain, foods and medicines that change the balance of
these signals affect whether we feel alert or drowsy and how well we
sleep. Caffeinated drinks such as coffee and drugs such as diet pills
and decongestants stimulate some parts of the brain and can cause insomnia,
or an inability to sleep. Many antidepressants suppress REM sleep. Heavy
smokers often sleep very lightly and have reduced amounts of REM sleep.
They also tend to wake up after 3 or 4 hours of sleep due to nicotine
withdrawal. Many people who suffer from insomnia try to solve the
problem with alcohol - the so-called night cap. While alcohol does
help people fall into light sleep, it also robs them of REM and the
deeper, more restorative stages of sleep. Instead, it keeps them in the
lighter stages of sleep, from which they can be awakened easily.
People
lose some of the ability to regulate their body temperature during REM,
so abnormally hot or cold temperatures in the environment can disrupt
this stage of sleep. If our REM sleep is disrupted one night, our bodies
don't follow the normal sleep cycle progression the next time we doze
off. Instead, we often slip directly into REM sleep and go through
extended periods of REM until we “catch up” on this stage of
sleep.
People
who are under anesthesia or in a coma are often said to be asleep.
However, people in these conditions cannot be awakened and do not
produce the complex, active brain wave patterns seen in normal sleep.
Instead, their brain waves are very slow and weak, sometimes all but
undetectable.
The
amount of sleep each person needs depends on many factors, including
age. Infants generally require about 16 hours a day, while teenagers
need about 9 hours on average. For most adults, 7 to 8 hours a night
appears to be the best amount of sleep, although some people may need as
few as 5 hours or as many as 10 hours of sleep each day. Women in the
first 3 months of pregnancy often need several more hours of sleep than
usual. The amount of sleep a person needs also increases if he or she
has been deprived of sleep in previous days. Getting too little sleep
creates a “sleep debt,” which is much like being overdrawn at
a bank. Eventually, your body will demand that the debt be repaid. We
don't seem to adapt to getting less sleep than we need; while we may
get used to a sleep-depriving schedule, our judgment, reaction time, and
other functions are still impaired.
People
tend to sleep more lightly and for shorter time spans as they get older,
although they generally need about the same amount of sleep as they
needed in early adulthood. About half of all people over 65 have
frequent sleeping problems, such as insomnia, and deep sleep stages in
many elderly people often become very short or stop completely. This
change may be a normal part of aging, or it may result from medical
problems that are common in elderly people and from the medications and
other treatments for those problems.
Experts
say that if you feel drowsy during the day, even during boring
activities, you haven't had enough sleep. If you routinely fall asleep
within 5 minutes of lying down, you probably have severe sleep
deprivation, possibly even a sleep disorder. Microsleeps, or very
brief episodes of sleep in an otherwise awake person, are another mark
of sleep deprivation. In many cases, people are not aware that they are
experiencing microsleeps. The widespread practice of “burning the
candle at both ends&” in western industrialized societies has
created so much sleep deprivation that what is really abnormal
sleepiness is now almost the norm.
Many studies make it clear that sleep deprivation
is dangerous. Sleep-deprived people who are tested by using a driving
simulator or by performing a hand-eye coordination task perform as
badly as or worse than those who are intoxicated. Sleep deprivation
also magnifies alcohol's effects on the body, so a fatigued person
who drinks will become much more impaired than someone who is well-rested.
Driver fatigue is responsible for an estimated 100,000 motor vehicle
accidents and 1500 deaths each year, according to the National Highway
Traffic Safety Administration. Since drowsiness is the brain's last
step before falling asleep, driving while drowsy can — and often
does — lead to disaster. Caffeine and other stimulants cannot
overcome the effects of severe sleep deprivation. The National Sleep
Foundation says that if you have trouble keeping your eyes focused,
if you can't stop yawning, or if you can't remember driving the last
few miles, you are probably too drowsy to drive safely.
Although
scientists are still trying to learn exactly why people need sleep,
animal studies show that sleep is necessary for survival. For example,
while rats normally live for two to three years, those deprived of REM
sleep survive only about 5 weeks on average, and rats deprived of all
sleep stages live only about 3 weeks. Sleep-deprived rats also develop
abnormally low body temperatures and sores on their tail and paws. The
sores may develop because the rats' immune systems become impaired.
Some studies suggest that sleep deprivation affects the immune system in
detrimental ways.
Sleep
appears necessary for our nervous systems to work properly. Too little
sleep leaves us drowsy and unable to concentrate the next day. It also
leads to impaired memory and physical performance and reduced ability to
carry out math calculations. If sleep deprivation continues,
hallucinations and mood swings may develop. Some experts believe sleep
gives neurons used while we are awake a chance to shut down and repair
themselves. Without sleep, neurons may become so depleted in energy or
so polluted with byproducts of normal cellular activities that they
begin to malfunction. Sleep also may give the brain a chance to exercise
important neuronal connections that might otherwise deteriorate from
lack of activity.
Deep
sleep coincides with the release of growth hormone in children and young
adults. Many of the body's cells also show increased production and
reduced breakdown of proteins during deep sleep. Since proteins are the
building blocks needed for cell growth and for repair of damage from
factors like stress and ultraviolet rays, deep sleep may truly be
“beauty sleep.” Activity in parts of the brain that control
emotions, decision-making processes, and social interactions is
drastically reduced during deep sleep, suggesting that this type of
sleep may help people maintain optimal emotional and social functioning
while they are awake. A study in rats also showed that certain
nerve-signaling patterns which the rats generated during the day were
repeated during deep sleep. This pattern repetition may help encode
memories and improve learning.
We
typically spend more than 2 hours each night dreaming. Scientists do not
know much about how or why we dream. Sigmund Freud, who greatly
influenced the field of psychology, believed dreaming was a “safety
valve” for unconscious desires. Only after 1953, when researchers
first described REM in sleeping infants, did scientists begin to
carefully study sleep and dreaming. They soon realized that the strange,
illogical experiences we call dreams almost always occur during REM
sleep. While most mammals and birds show signs of REM sleep, reptiles
and other cold-blooded animals do not.
REM sleep begins with signals from an area at
the base of the brain called the pons (see figure
2). These signals travel to a brain region called the thalamus,
which relays them to the cerebral cortex — the outer
layer of the brain that is responsible for learning, thinking, and
organizing information. The pons also sends signals that shut off
neurons in the spinal cord, causing temporary paralysis of the limb
muscles. If something interferes with this paralysis, people will
begin to physically “act out” their dreams — a rare,
dangerous problem called REM sleep behavior disorder. A person
dreaming about a ball game, for example, may run headlong into furniture
or blindly strike someone sleeping nearby while trying to catch a
ball in the dream.
REM
sleep stimulates the brain regions used in learning. This may be
important for normal brain development during infancy, which would
explain why infants spend much more time in REM sleep than adults (see Sleep: A Dynamic Activity).
Like deep sleep, REM sleep is associated with increased production of
proteins. One study found that REM sleep affects learning of certain
mental skills. People taught a skill and then deprived of non-REM sleep
could recall what they had learned after sleeping, while people deprived
of REM sleep could not.
Some
scientists believe dreams are the cortex's attempt to find meaning in
the random signals that it receives during REM sleep. The cortex is the
part of the brain that interprets and organizes information from the
environment during consciousness. It may be that, given random signals
from the pons during REM sleep, the cortex tries to interpret these
signals as well, creating a “story” out of fragmented brain
activity.
Circadian
rhythms are regular changes in mental and physical characteristics
that occur in the course of a day (circadian is Latin for
“around a day”). Most circadian rhythms are controlled by the
body's biological “clock.” This clock, called the suprachiasmatic
nucleus or SCN (seefigure
2), is actually a pair of pinhead-sized brain structures that
together contain about 20,000 neurons. The SCN rests in a part of the
brain called the hypothalamus, just above the point where the
optic nerves cross. Light that reaches photoreceptors in the retina
(a tissue at the back of the eye) creates signals that travel along the
optic nerve to the SCN.
Signals
from the SCN travel to several brain regions, including the pineal
gland, which responds to light-induced signals by switching off
production of the hormone melatonin. The body's level of melatonin
normally increases after darkness falls, making people feel drowsy. The
SCN also governs functions that are synchronized with the sleep/wake
cycle, including body temperature, hormone secretion, urine production,
and changes in blood pressure.
By
depriving people of light and other external time cues, scientists have
learned that most people's biological clocks work on a 25-hour cycle
rather than a 24-hour one. But because sunlight or other bright lights
can reset the SCN, our biological cycles normally follow the 24-hour
cycle of the sun, rather than our innate cycle. Circadian rhythms can be
affected to some degree by almost any kind of external time cue, such as
the beeping of your alarm clock, the clatter of a garbage truck, or the
timing of your meals. Scientists call external time cues zeitgebers
(German for “time givers”).
When
travelers pass from one time zone to another, they suffer from disrupted
circadian rhythms, an uncomfortable feeling known as jet lag. For
instance, if you travel from California to New York, you
“lose” three hours according to your body's clock. You will feel
tired when the alarm rings at 8 a.m. the next morning because, according
to your body's clock, it is still 5 a.m. It usually takes several days
for your body's cycles to adjust to the new time.
To
reduce the effects of jet lag, some doctors try to manipulate the
biological clock with a technique called light therapy. They expose
people to special lights, many times brighter than ordinary household
light, for several hours near the time the subjects want to wake up.
This helps them reset their biological clocks and adjust to a new time
zone.
Symptoms
much like jet lag are common in people who work nights or who perform
shift work. Because these people's work schedules are at odds with
powerful sleep-regulating cues like sunlight, they often become
uncontrollably drowsy during work, and they may suffer insomnia or other
problems when they try to sleep. Shift workers have an increased risk of
heart problems, digestive disturbances, and emotional and mental
problems, all of which may be related to their sleeping problems. The
number and severity of workplace accidents also tend to increase during
the night shift. Major industrial accidents attributed partly to errors
made by fatigued night-shift workers include the Exxon Valdez oil spill
and the Three Mile Island and Chernobyl nuclear power plant accidents.
One study also found that medical interns working on the night shift are
twice as likely as others to misinterpret hospital test records, which
could endanger their patients. It may be possible to reduce
shift-related fatigue by using bright lights in the workplace,
minimizing shift changes, and taking scheduled naps.
Many
people with total blindness experience life-long sleeping problems
because their retinas are unable to detect light. These people have a
kind of permanent jet lag and periodic insomnia because their circadian
rhythms follow their innate cycle rather than a 24-hour one. Daily
supplements of melatonin may improve night-time sleep for such patients.
However, since the high doses of melatonin found in most supplements can
build up in the body, long-term use of this substance may create new
problems. Because the potential side effects of melatonin supplements
are still largely unknown, most experts discourage melatonin use by the
general public.
Sleep
and sleep-related problems play a role in a large number of human
disorders and affect almost every field of medicine. For example,
problems like stroke and asthma attacks tend to occur more frequently
during the night and early morning, perhaps due to changes in hormones,
heart rate, and other characteristics associated with sleep. Sleep also
affects some kinds of epilepsy in complex ways. REM sleep seems to help
prevent seizures that begin in one part of the brain from spreading to
other brain regions, while deep sleep may promote the spread of these
seizures. Sleep deprivation also triggers seizures in people with some
types of epilepsy.
Neurons
that control sleep interact closely with the immune system. As anyone
who has had the flu knows, infectious diseases tend to make us feel
sleepy. This probably happens because cytokines, chemicals our
immune systems produce while fighting an infection, are powerful
sleep-inducing chemicals. Sleep may help the body conserve energy and
other resources that the immune system needs to mount an attack.
Sleeping
problems occur in almost all people with mental disorders, including
those with depression and schizophrenia. People with depression, for
example, often awaken in the early hours of the morning and find
themselves unable to get back to sleep. The amount of sleep a person
gets also strongly influences the symptoms of mental disorders. Sleep
deprivation is an effective therapy for people with certain types of
depression, while it can actually cause depression in other people.
Extreme sleep deprivation can lead to a seemingly psychotic state of
paranoia and hallucinations in otherwise healthy people, and disrupted
sleep can trigger episodes of mania (agitation and hyperactivity) in
people with manic depression.
Sleeping
problems are common in many other disorders as well, including
Alzheimer's disease, stroke, cancer, and head injury. These sleeping
problems may arise from changes in the brain regions and
neurotransmitters that control sleep, or from the drugs used to control
symptoms of other disorders. In patients who are hospitalized or who
receive round-the-clock care, treatment schedules or hospital routines
also may disrupt sleep. The old joke about a patient being awakened by a
nurse so he could take a sleeping pill contains a grain of truth. Once
sleeping problems develop, they can add to a person's impairment and
cause confusion, frustration, or depression. Patients who are unable to
sleep also notice pain more and may increase their requests for pain
medication. Better management of sleeping problems in people who have
other disorders could improve these patients' health and quality of
life.
At
least 40 million Americans each year suffer from chronic, long-term
sleep disorders each year, and an additional 20 million experience
occasional sleeping problems. These disorders and the resulting sleep
deprivation interfere with work, driving, and social activities. They
also account for an estimated $16 billion in medical costs each year,
while the indirect costs due to lost productivity and other factors are
probably much greater. Doctors have described more than 70 sleep
disorders, most of which can be managed effectively once they are
correctly diagnosed. The most common sleep disorders include insomnia,
sleep apnea, restless legs syndrome, and narcolepsy.
Almost
everyone occasionally suffers from short-term insomnia. This problem can
result from stress, jet lag, diet, or many other factors. Insomnia
almost always affects job performance and well-being the next day. About
60 million Americans a year have insomnia frequently or for extended
periods of time, which leads to even more serious sleep deficits.
Insomnia tends to increase with age and affects about 40 percent of
women and 30 percent of men. It is often the major disabling symptom of
an underlying medical disorder.
For
short-term insomnia, doctors may prescribe sleeping pills. Most sleeping
pills stop working after several weeks of nightly use, however, and
long-term use can actually interfere with good sleep. Mild insomnia
often can be prevented or cured by practicing good sleep habits (see “Tips
for a Good Night's Sleep”). For more serious cases of
insomnia, researchers are experimenting with light therapy and other
ways to alter circadian cycles.
Sleep
apnea is a disorder of interrupted breathing during sleep. It usually
occurs in association with fat buildup or loss of muscle tone with
aging. These changes allow the windpipe to collapse during breathing
when muscles relax during sleep (seefigure
3). This problem, called obstructive sleep apnea, is usually
associated with loud snoring (though not everyone who snores has this
disorder). Sleep apnea also can occur if the neurons that control
breathing malfunction during sleep.
During
an episode of obstructive apnea, the person's effort to inhale air
creates suction that collapses the windpipe. This blocks the air flow
for 10 seconds to a minute while the sleeping person struggles to
breathe. When the person's blood oxygen level falls, the brain
responds by awakening the person enough to tighten the upper airway
muscles and open the windpipe. The person may snort or gasp, then resume
snoring. This cycle may be repeated hundreds of times a night. The
frequent awakenings that sleep apnea patients experience leave them
continually sleepy and may lead to personality changes such as
irritability or depression. Sleep apnea also deprives the person of
oxygen, which can lead to morning headaches, a loss of interest in sex,
or a decline in mental functioning. It also is linked to high blood
pressure, irregular heartbeats, and an increased risk of heart attacks
and stroke. Patients with severe, untreated sleep apnea are two to three
times more likely to have automobile accidents than the general
population. In some high-risk individuals, sleep apnea may even lead to
sudden death from respiratory arrest during sleep.
An
estimated 18 million Americans have sleep apnea. However, few of them
have had the problem diagnosed. Patients with the typical features of
sleep apnea, such as loud snoring, obesity, and excessive daytime
sleepiness, should be referred to a specialized sleep center that can
perform a test called polysomnography. This test records the
patient's brain waves, heartbeat, and breathing during an entire
night. If sleep apnea is diagnosed, several treatments are available.
Mild sleep apnea frequently can be overcome through weight loss or by
preventing the person from sleeping on his or her back. Other people may
need special devices or surgery to correct the obstruction. People with
sleep apnea should never take sedatives or sleeping pills, which can
prevent them from awakening enough to breathe.
Restless
legs syndrome (RLS), a familial disorder causing unpleasant
crawling, prickling, or tingling sensations in the legs and feet and an
urge to move them for relief, is emerging as one of the most common
sleep disorders, especially among older people. This disorder, which
affects as many as 12 million Americans, leads to constant leg movement
during the day and insomnia at night. Severe RLS is most common in
elderly people, though symptoms may develop at any age. In some cases,
it may be linked to other conditions such as anemia, pregnancy, or
diabetes.
Many
RLS patients also have a disorder known as periodic limb movement
disorder or PLMD, which causes repetitive jerking movements
of the limbs, especially the legs. These movements occur every 20 to 40
seconds and cause repeated awakening and severely fragmented sleep. In
one study, RLS and PLMD accounted for a third of the insomnia seen in
patients older than age 60.
RLS
and PLMD often can be relieved by drugs that affect the neurotransmitter
dopamine, suggesting that dopamine abnormalities underlie these
disorders' symptoms. Learning how these disorders occur may lead to
better therapies in the future.
Narcolepsy
affects an estimated 250,000 Americans. People with narcolepsy have
frequent "sleep attacks" at various times of the day, even if
they have had a normal amount of night-time sleep. These attacks last
from several seconds to more than 30 minutes. People with narcolepsy
also may experience cataplexy (loss of muscle control during emotional
situations), hallucinations, temporary paralysis when they awaken, and
disrupted night-time sleep. These symptoms seem to be features of REM
sleep that appear during waking, which suggests that narcolepsy is a
disorder of sleep regulation. The symptoms of narcolepsy typically
appear during adolescence, though it often takes years to obtain a
correct diagnosis. The disorder (or at least a predisposition to it) is
usually hereditary, but it occasionally is linked to brain damage from a
head injury or neurological disease.
Once
narcolepsy is diagnosed, stimulants, antidepressants, or other drugs can
help control the symptoms and prevent the embarrassing and dangerous
effects of falling asleep at improper times. Naps at certain times of
the day also may reduce the excessive daytime sleepiness.
In
1999, a research team working with canine models identified a gene that
causes narcolepsy — a breakthrough that brings a cure for this disabling
condition within reach. The gene, hypocretin receptor 2, codes for a
protein that allows brain cells to receive instructions from other
cells. The defective versions of the gene encode proteins that cannot
recognize these messages, perhaps cutting the cells off from messages
that promote wakefulness. The researchers know that the same gene exists
in humans, and they are currently searching for defective versions in
people with narcolepsy.
Sleep
research is expanding and attracting more and more attention from
scientists. Researchers now know that sleep is an active and dynamic
state that greatly influences our waking hours, and they realize that we
must understand sleep to fully understand the brain. Innovative
techniques, such as brain imaging, can now help researchers understand
how different brain regions function during sleep and how different
activities and disorders affect sleep. Understanding the factors that
affect sleep in health and disease also may lead to revolutionary new
therapies for sleep disorders and to ways of overcoming jet lag and the
problems associated with shift work. We can expect these and many other
benefits from research that will allow us to truly understand sleep's
impact on our lives.
Adapted
from “When You Can't Sleep: The ABCs of ZZZs,” by the National
Sleep Foundation.
Set a schedule:
Go to bed at a set time each night and get up at the
same time each morning. Disrupting this schedule may lead to insomnia.
“Sleeping in” on weekends also makes it harder to
wake up early on Monday morning because it re-sets your sleep
cycles for a later awakening.
Exercise:
Try to exercise 20 to 30 minutes a day. Daily exercise
often helps people sleep, although a workout soon before bedtime
may interfere with sleep. For maximum benefit, try to get your
exercise about 5 to six hours before going to bed.
Avoid caffeine, nicotine, and alcohol:
Avoid drinks that contain caffeine which acts as a
stimulant and keeps people awake. Sources of caffeine include
coffee, chocolate, soft drinks, non-herbal teas, diet drugs, and
some pain relievers. Smokers tend to sleep very lightly and often
wake up in the early morning due to nicotine withdrawal. Alcohol
robs people of deep sleep and REM sleep and keeps them in the
lighter stages of sleep.
Relax before bed:
A warm bath, reading, or another relaxing routine can
make it easier to fall sleep. You can train yourself to associate
certain restful activities with sleep and make them part of your
bedtime ritual.
Sleep until sunlight:
If possible, wake up with the sun, or use very bright
lights in the morning. Sunlight helps the body's internal biological
clock reset itself each day. Sleep experts recommend exposure
to an hour of morning sunlight for people having problems falling
asleep.
Don't lie in bed awake:
If you can't get to sleep, don't just lie in bed. Do
something else, like reading, watching television, or listening
to music, until you feel tired. The anxiety of being unable to
fall asleep can actually contribute to insomnia.
Control your room temperature:
Maintain a comfortable temperature in the bedroom.
Extreme temperatures may disrupt sleep or prevent you from falling
asleep.
See a doctor if your sleeping problem continues:
If you have trouble falling asleep night after night,
or if you always feel tired the next day, then you may have a
sleep disorder and should see a physician. Your primary care physician
may be able to help you; if not, you can probably find a sleep
specialist at a major hospital near you. Most sleep disorders
can be treated effectively, so you can finally get that good night's
sleep you need.
For more information,
write or call the NINDS Brain Resources and Information Network
(BRAIN) at:
As of March 23, 2007 at 10:54 a.m. (-0500), the U.S. population was 301,442,343. With new estimates
that about seven percent of the population suffers from obstructive sleep apnea, that means
there are potentially 21,100,964 apneics in the U.S.
Apnea around the world ~~
As of March 23, 2007 at 10:54 a.m. (-0500), the world population was 6,584,093,711. With new estimates
that about seven percent of the population suffers from obstructive sleep apnea, that means
there are potentially 460,886,560 apneics in the world.
Awake In Philly is a community education group for individuals who have been
diagnosed with at least one of the recognized sleep disorders, as well as anyone
else impacted by those with sleep disorders. The information contained in this
site is intended to provide support, guidance, and encouragement to others contending
with the many challenges of sleep disorders. The goals of Awake In Philly are to support, educate, and inform those who feel the impact of sleep disorders,
as well as the general public, and is not intended to replace medical
advice, nor is any information to be misinterpreted as an attempt to diagnose,
treat, cure, or prevent any disease.
If you have questions about any of the medical conditions mentioned on this website, especially if you suspect that you (or someone you know) has sleep apnea, please
contact a qualified medical professional immediately. Medical advice should only come from qualified, licensed, and trained healthcare professionals.
Citation: David F. Jackson.
“Understanding_Sleep.shtml”, located at . Awake In Philly Community Education Group. Last Modified on Sunday, 03-Jun-2007 11:25:52 EDT. (Page last visited: Wednesday, 23-Jul-2008 16:02:17 EDT).
