When we fall asleep, muscles in the body relax—including the muscles that support the airway as it passes from our mouth to our lungs. Sleep apnea is caused when the muscles in the neck relax too much—so much so that it actually becomes difficult to breathe. In many cases, the airway collapses entirely and breathing is impossible—until the sleeper awakens and muscle tone is restored—thus allowing the airway to open and breathing to resume.

Sleep apnea is hard on your heart…and considered to be life threatening.

During these periods of difficulty breathing, the body’s oxygen level can fall to dangerously low levels. Untreated sleep apnea has been conclusively linked to weakening of the right wall of the heart muscle, is a contributor to hypertension (high blood pressure), and has been demonstrated to increase blood pressure during sleep as much as 20 to 40 points above normal. It is conjectured that these “phantom” spikes in blood pressure—called phantom because they are transient during sleep and are not visible during waking hours—may be responsible for what are known as “silent strokes.” Silent strokes do not dramatically disable an individual. Instead, they rob him or her of cognitive ability (memory) in one small section of the brain at a time.

In addition to these problems, sleep apnea wreaks havoc with the quality of the apneic’s sleep. In truth, a patient with sleep apnea is only able to sleep in small bursts. Why? Because he or she has to continually awaken from sleep—to restore muscle tone to the collapsed airway—to allow him or her to resume breathing.

The cycle of apnea:

1. The apneic patient falls asleep
2. Muscle tone in the body relaxes
3. Airway narrows and/or collapses, causing breathing to be difficult or impossible.
4. The collapse of the airway may cause loud snoring, snorts, pauses in airflow, and labored breathingŠ
5. Oxygen levels begins to fall.
6. The apneic patient continues to struggle for breath…time goes by…10, 20, 40 seconds…and longer…
7. Heart rate falls below normal—there is decreased oxygen to pump through the body.
8. Brain senses low oxygen/high carbon dioxide level, releases jolt of adrenaline—“fight or flight” response—to awaken brain and body and prevent suffocation.
9. Sleeper awakens briefly, takes five or six large breaths, breathing in oxygen and blowing off excess carbon dioxide (CO2). Sleeper typically does not remember arousal. Sleeper often repositions him or herself on the bed.
10. Heart rate speeds up in response to rush of adrenaline—now pumps above normal heart rate.
11. Oxygen/carbon dioxide levels return to near normal. Brain allows sleeper to resume sleeping.
12. Sleeper falls asleep.
13. Muscle tone relaxes…

Sleep Apnea: Phantom of the Night

It is not unusual for an apneic patient to have over one hundred arousals per night due to apnea, though he or she most likely will not remember any of them. This makes apnea suffers—especially those who live alone or sleep in bedrooms separate from their partners—vulnerable to not having their condition diagnosed for many years, if ever.

Severity of sleep apnea is measured by three variables.

1. The number of apneic episodes per hour—also known as a respiratory disturbance index (RDI).

   An RDI of 5-15/hr is considered mild sleep apnea.
   An RDI of 16-30/hr is considered moderate sleep apnea.
   An RDI of +30/hr is considered severe sleep apnea.

2. Levels of oxygen desaturation. Normal waking oxygen saturation in a healthy child or adult is 96-99%. Normal asleep oxygen saturation in a healthy child or adult is 94-98%.

   All oxygen desaturations <90% during sleep are considered medically significant.

3. Daytime symptoms. Sleep apnea’s effect on daytime performance is considered in treatment options.