What is Sleep Apnea?
Who Gets Sleep Apnea?
What Causes Sleep Apnea?
How is Normal Breathing Restored During Sleep?
What are the Effects of Sleep Apnea?
When Should Sleep Apnea be Suspected?
How is Sleep Apnea Diagnosed?
How is Sleep Apnea Treated?
For More Information
WHAT IS SLEEP APNEA? <<Back to Top>>
Sleep apnea is a serious, potentially lifethreatening
condition that is far more common
than generally understood. First
described in 1965, sleep apnea is a breathing
disorder characterized by brief interruptions
of breathing during sleep. It owes its name
to a Greek word, apnea, meaning "want of
breath." There are two types of sleep apnea:
central and obstructive. Central sleep
apnea, which is less common, occurs when
the brain fails to send the appropriate signals
to the breathing muscles to initiate respirations.
Obstructive sleep apnea is far
more common and occurs when air cannot
flow into or out of the person's nose or
mouth although efforts to breathe continue.
In a given night, the number of involuntary
breathing pauses or "apneic events" may be
as high as 20 to 30 or more per hour. These
breathing pauses are almost always accompanied
by snoring between apnea episodes,
although not everyone who snores has this
condition. Sleep apnea can also be characterized
by choking sensations. The frequent
interruptions of deep, restorative sleep often
lead to early morning headaches and excessive
Early recognition and treatment of sleep
apnea is important because it may be associated
with irregular heartbeat, high blood
pressure, heart attack, and stroke.
WHO GETS SLEEP APNEA?
Sleep apnea occurs in all age groups and
both sexes but is more common in men (it
may be underdiagnosed in women) and possibly
young African Americans. It has been
estimated that as many as 18 million
Americans have sleep apnea. Four percent
of middle-aged men and 2 percent of middle-
aged women have sleep apnea along
with excessive daytime sleepiness. People
most likely to have or develop sleep apnea
include those who snore loudly and also are
overweight, or have high blood pressure, or
have some physical abnormality in the nose,
throat, or other parts of the upper airway.
Sleep apnea seems to run in some families,
suggesting a possible genetic basis.
WHAT CAUSES SLEEP APNEA?<<Back to Top>>
Certain mechanical and structural problems
in the airway cause the interruptions in
breathing during sleep. In some people,
apnea occurs when the throat muscles and
tongue relax during sleep and partially block
the opening of the airway. When the muscles
of the soft palate at the base of the
tongue and the uvula (the small fleshy tissue
hanging from the center of the back of the
throat) relax and sag, the airway becomes
blocked, making breathing labored and
noisy and even stopping it altogether. Sleep
apnea also can occur in obese people when
an excess amount of tissue in the airway causes it to be narrowed. With a
narrowed airway, the person continues
his or her efforts to breathe, but
air cannot easily flow into or out of
the nose or mouth. Unknown to the
person, this results in heavy snoring,
periods of no breathing, and frequent
arousals (causing abrupt changes
from deep sleep to light sleep).
Ingestion of alcohol and sleeping
pills increases the frequency and
duration of breathing pauses in people
with sleep apnea.
HOW IS NORMAL BREATHING
RESTORED DURING SLEEP?
During the apneic event, the person
is unable to breathe in oxygen and to
exhale carbon dioxide, resulting in
low levels of oxygen and increased
levels of carbon dioxide in the blood.
The reduction in oxygen and increase
in carbon dioxide alert the brain to
resume breathing and cause an
arousal. With each arousal, a signal
is sent from the brain to the upper
airway muscles to open the airway;
breathing is resumed, often with a
loud snort or gasp. Frequent
arousals, although necessary for
breathing to restart, prevent the
patient from getting enough restorative,
WHAT ARE THE EFFECTS OF
Because of the serious disturbances
in their normal sleep patterns, people
with sleep apnea often feel very
sleepy during the day and their concentration
and daytime performance
suffer. The consequences of sleep
apnea range from annoying to life threatening.
They include depression,
irritability, sexual dysfunction,
learning and memory difficulties,
and falling asleep while at work, on
the phone, or driving. It has been
estimated that up to 50 percent of
sleep apnea patients have high blood
pressure. Although it is not known
with certainty if there is a cause and
effect relationship, it appears that
sleep apnea contributes to high
blood pressure. Risk for heart attack
and stroke may also increase in those
with sleep apnea. In addition, sleep
apnea is sometimes implicated in
sudden infant death syndrome.
WHEN SHOULD SLEEP APNEA
<<Back to Top>>
For many sleep apnea patients, their
spouses are the first ones to suspect
that something is wrong, usually
from their heavy snoring and apparent struggle to breathe. Coworkers
or friends of the sleep apnea victim
may notice that the individual falls
asleep during the day at inappropriate
times (such as while driving a
working, or talking). The patient
often does not know he or she has
problem and may not believe it when
told. It is important that the person
see a doctor for evaluation of the
HOW IS SLEEP APNEA
In addition to the primary care
physician, pulmonologists, neurologists,
or other physicians with specialty
training in sleep disorders may
be involved in making a definitive
diagnosis and initiating treatment.
Diagnosis of sleep apnea is not simple
because there can be many different
reasons for disturbed sleep.
Several tests are available for evaluating
a person for sleep apnea.
Polysomnography is a test that
records a variety of body functions
during sleep, such as the electrical
activity of the brain, eye movement,
muscle activity, heart rate, respiratory
effort, air flow, and blood
oxygen levels. These tests are used
both to diagnose sleep apnea and to
determine its severity.
The Multiple Sleep Latency Test
(MSLT) measures the speed of falling
asleep. In this test, patients are
given several opportunities to fall
asleep during the course of a day
when they would normally be awake.
For each opportunity, time to fall
asleep is measured. People without
sleep problems usually take an average
of 10 to 20 minutes to fall
asleep. Individuals who fall asleep in
less than 5 minutes are likely to require some treatment for sleep disorders.
The MSLT may be useful to
measure the degree of excessive daytime
sleepiness and to rule out other
types of sleep disorders.
Diagnostic tests usually are performed
in a sleep center, but new technology
may allow some sleep studies to be
conducted in the patient's home.
HOW IS SLEEP APNEA
The specific therapy for sleep apnea is
tailored to the individual patient
based on medical history, physical
examination, and the results of
polysomnography. Medications are
generally not effective in the treatment
of sleep apnea. Oxygen administration
may safely benefit certain
patients but does not eliminate sleep
apnea or prevent daytime sleepiness.
Thus, the role of oxygen in the treatment
of sleep apnea is controversial,
and it is difficult to predict which
patients will respond well. It is important
that the effectiveness of the
selected treatment be verified; this is
usually accomplished by polysomnography.
Behavioral changes are an important
part of the treatment program, and
in mild cases behavioral therapy may
be all that is needed. The individual
should avoid the use of alcohol,
tobacco, and sleeping pills, which
make the airway more likely to collapse
during sleep and prolong the
apneic periods. Overweight persons
can benefit from losing weight. Even
a 10 percent weight loss can reduce
the number of apneic events for most
patients. In some patients with mild
sleep apnea, breathing pauses occur
only when they sleep on their backs.
In such cases, using pillows and other
devices that help them sleep in a side
position is often helpful.
Physical or Mechanical
Nasal continuous positive airway
pressure (CPAP) is the most common
effective treatment for sleep apnea.
In this procedure, the patient wears a
mask over the nose during sleep, and
pressure from an air blower forces air
through the nasal passages. The air
pressure is adjusted so that it is just enough to prevent the throat from
collapsing during sleep. The pressure
is constant and continuous.
Nasal CPAP prevents airway closure
while in use, but apnea episodes
return when CPAP is stopped or
Variations of the CPAP device
attempt to minimize side effects that
sometimes occur, such as nasal irritation
and drying, facial skin irritation,
abdominal bloating, mask
leaks, sore eyes, and headaches.
Some versions of CPAP vary the
pressure to coincide with the person's
breathing pattern, and others
start with low pressure, slowly
increasing it to allow the person to
fall asleep before the full prescribed
pressure is applied.
Dental appliances that reposition
the lower jaw and the tongue have
been helpful to some patients with
mild sleep apnea or who snore but
do not have apnea. Possible side
effects include damage to teeth, soft
tissues, and the jaw joint. A dentist
or orthodontist is often the one to fit
the patient with such a device.
Surgery<<Back to Top>>
Some patients with sleep apnea may
need surgery. Although several surgical
procedures are used to increase
the size of the airway, none of them
is completely successful or without
risks. More than one procedure may
need to be tried before the patient
realizes any benefits.
Some of the more common procedures
include removal of adenoids
and tonsils (especially in children),
nasal polyps or other growths, or
other tissue in the airway and correction
of structural deformities.
Younger patients seem to benefit
from these surgical procedures more
than older patients. Uvulopalatopharyngoplasty (UPPP) is
a procedure used to remove excess tissue
at the back of the throat (tonsils,
uvula, and part of the soft palate).
The success of this technique may
range from 30 to 50 percent. The
long-term side effects and benefits are
not known, and it is difficult to predict
which patients will do well with this
(LAUP) is done to eliminate snoring
but has not been shown to be effective
in treating sleep apnea.
involves using a laser device to
eliminate tissue in the back of the
throat. Like UPPP, LAUP may
decrease or eliminate snoring but not
sleep apnea itself. Elimination of snoring,
the primary symptom of sleep
apnea, without influencing the condition
may carry the risk of delaying the
diagnosis and possible treatment of
sleep apnea in patients who elect
LAUP. To identify possible underlying
sleep apnea, sleep studies are usually
required before LAUP is performed.
Tracheostomy is used in persons with
severe, life-threatening sleep apnea. In
this procedure, a small hole is made in
the windpipe and a tube is inserted
into the opening. This tube stays
closed during waking hours, and the
person breathes and speaks normally.
It is opened for sleep so that air flows
directly into the lungs, bypassing any
upper airway obstruction. Although
this procedure is highly effective, it is
an extreme measure that is poorly tolerated
by patients and rarely used.
Other procedures. Patients in whom
sleep apnea is due to deformities of the
lower jaw may benefit from surgical
reconstruction. Finally, surgical procedures
to treat obesity are sometimes
recommended for sleep apnea patients
who are morbidly obese.
U.S. DEPARTMENT OF HEALTH
AND HUMAN SERVICES
Public Health Service -
National Institutes of Health
National Heart, Lung, and
NIH Publication No. 95-3798,
Information about sleep
disorders research can be
obtained from the NCSDR.
In addition, the NHLBI
Information Center can
provide you with sleep
education materials as well
as other publications relating
to heart, lung, and
National Center on Sleep -
Two Rockledge Centre,
6701 Rockledge Drive
Bethesda, MD 20892-7920
FAX: (301) 480-3451
NHLBI Information Center<<Back to Top>>
P.O. Box 30105
Bethesda, MD 20824-0105
FAX: (301) 251-1223