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    About Sleep Apnea



    Introduction to SDB

    Sleep-disordered breathing (SDB) is a general term for a sleep disorder with apneas and hypopneas. Apnea is a cessation of airflow for ten seconds or longer (Apnea comes from Greek and literally means "without breath"). Hypopnea is a 50% or greater decrease in air flow for ten seconds or longer.

    Both apneas and hypopneas cause sudden sleep arousals in which an individual wakes up in order to resume breathing but still not remember any interruption of sleep. Some arousals simply cause the sleeper to shift into a lighter stage of sleep. In either case, the arousal lessens the quality of sleep. Apneas and hypopneas may cause blood oxygen levels to drop.

    Apneas and hypopneas result from upper airway obstruction, either full or partial, or a dysfunction of the body's automatic drive to breathe.



    Sleep Apnea Syndrome (SAS)

    There are three types of sleep apnea - obstructive sleep apnea, central sleep apnea, and mixed apnea.

    Obstructive sleep apnea (OSA) is the most common type of sleep apnea. It occurs when the upper airway closes and requires a great effort to continue breathing. The primary causes of upper airway obstruction are lack of muscle tone during sleep, excess tissue in the upper airway, and anatomical abnormalities in the upper airway and jaw. (learn more)

    Central sleep apnea (CSA) affects only 5-10% of the sleep apnea population. It occurs when breathing stops but the airway remains open. This cessation of breathing results from the body's failure to breathe automatically or in other words, the brain fails to signal the muscles to breathe.

    Mixed apnea is a mixture of both obstructive sleep apnea and central sleep apnea.


    Sleep Apnea Symptoms

    Hypertension and decreased blood oxygen levels are common symptoms for people with sleep apnea, but these are not easily detected. Here are the symptoms that are easiest to identify without medical diagnostic:
    Excessive sleepiness
    Snoring (most familiar with obstructive sleep apnea)
    Witnessed apneas or irregular breathing during sleep (such as gasping, long pauses)
    Impaired concentration
    Impaired memory
    Morning headaches
    Sexual dysfunction



    Obstructive Sleep Apnea

    Obstructive Sleep Apnea (OSA) is a common disorder. Estimates for the number of people in the US with Obstructive Sleep Apnea vary depending on the criteria researchers use for the study. Conservative estimates, however, put the number of adults with OSA at approximately 20 million. Obstructive Sleep Apnea occurs because of upper airway obstructions that can cause you to snore or to stop breathing.

    Obstructions occur during sleep for two primary reasons: lack of muscle tone and gravity. Excess tissue in the upper airway and anatomic abnormalities compound these factors. During sleep, especially in REM sleep, our bodies relax, and muscle tissues like the tongue and soft palate lose their slight rigidity. Because we tend to sleep lying down, gravity pulls these tissues toward the back of the throat and closes the upper airway.

    Snoring is the symptom that is most commonly associated with Obstructive Sleep Apnea. It happens when the upper airway becomes partially obstructed. As air moves through the limited space, it causes the soft tissues of the throat, uvula, and soft palate to vibrate. These vibrations create the sound we recognize as snoring.

    When these tissues obstruct the upper airway completely, they prevent breathing. They actually work to suffocate the sleeper. The sleeper wakes up enough to regain control of the upper airway, breathe again, and then fall back to sleep. This happens from dozens to hundreds of times per night for people with obstructive sleep apnea, but they usually don't remember waking up.

    Each obstruction deprives the body of oxygen and forces it to retain carbon dioxide that it would normally exhale. As a result, the body's blood gases get out of balance, and the body is subjected to a toxic environment. When the body sets off 'alarms' that it needs more oxygen, the brain wakes the sleeper, breathing resumes, and the individual falls back to sleep until the next obstruction occurs. These obstructions increase heart rate, raise blood pressure, and eventually blunt the body's automatic response system, resulting in increasingly more severe apneas and hypopneas.

    The brief wake-ups that people with OSA experience also diminish their quality of sleep, resulting in sleep deprivation. The symptoms of sleep deprivation may be what bring most people with obstructive sleep apnea to see their physician. Symptoms like excessive daytime sleepiness, poor concentration, poor memory, and even depression are common for people with obstructive sleep apnea.


    Risk Factors for OSA

    Physicians have identified a number of factors that may increase a person's risk of having obstructive sleep apnea:
    Obesity
    Snoring
    Family history of OSA or snoring
    Small upper airway (large tongue, large uvula, recessed chin, excess tissue in the throat and/or soft palate)

    People who are overweight have a greater risk of sleep apnea. In addition, the heavier a person becomes the more severe obstructive sleep apnea becomes, so most physicians recommend exercise and a healthy diet for people with OSA.

    Researchers have discovered that REM sleep deprivation increases people's appetites and decreases their energy levels. Consequently, researchers believe that OSA might initiate a downward spiral for some people because as they lose sleep, they eat more, gain weight, and increase the severity of their OSA.


    OSA in Children

    It is estimated that 11% of all children have SDB. For obstructive sleep apnea the statistics vary, but general consensus is that the condition affects somewhere between 0.7% and 3% of all children.

    Habitual snoring affects approximately 3.2% – 12% of youngsters and is often the first and most obvious indicator of obstructive sleep apnea. Other indicators include noisy breathing, increased work of breathing, apneas with noisy resumption of breathing and chronic mouth breathing.