These terms describe parts of the
continuum of airway collapsibility expressed as
sleep-disordered breathing. This spectrum ranges from
slight vibration of tissues at its mildest to death from
asphyxiation at its severe extreme. Between lies
pathologic snoring and periods of complete airway
closure and breathing cessation called "apnea".
Some of the most serious chronic
diseases of man have been associated with snoring and
sleep apnea, including: stroke, hypertension (high blood
pressure), myocardial infarction (heart attack),
arteriosclerosis (hardening of the arteries), cardiac
arrhythmias (irregular pulse), diabetes,
gastro-esophageal reflux disorder (GERD), polycythemia
vera (thickening of the blood) and others.
Sleep disordered breathing also
disrupts the normal patterns of brain activity and
relaxation, precluding restorative sleep. Overwhelming
daytime sleepiness contributes to the risk of accident
and injury from decreased attention span, judgment and
reflex. The risk of automobile accident in the untreated
sleep apnea patient is about 8 times that of the normal
sleeper. Work productivity and safety suffer.
During the increasing muscular
relaxation of deepening sleep, the airway can become
increasingly flaccid. The relaxing tongue falls back,
sealing against the back of the throat during the
sucking, negative pressure of the attempt to take a
breath. Snoring is the vibration of the uvula, soft
palate and throat walls against the tongue during the
inspiratory phase of breathing, with reduced airflow due
to increased resistance. As collapsibility increases,
complete closure can occur.
In either narrowing (hypopnea) or
closing (apnea) events, oxygen levels of the blood can
drop precipitously triggering a response of the brain to
prevent asphyxia. This "sympathetic discharge" of
adrenaline, corticosteroids and other agents raise blood
pressure, pulse rate, muscle activity and brain activity
to protect the unconscious sleeper from death.
The sleep apnea patient may have
these events occur up to 600 times or more per night
resulting in fragmented, non-refreshing sleep as well as
chronic activation of the sympathetic nervous system.
This activation is thought to be the reason for such
devastating long-term negative effects on
cardio-pulmonary health. Untreated for nine years, sleep
apnea patients may lose 20-50% of lifespan.