Sleep Apnea

Obstructive sleep apnea is a common disorder. Estimates for the number of North Americans with obstructive sleep apnea vary depending on the criteria researchers use for the study. Conservative estimates, however, put the number of adult North Americans with obstructive sleep apnea at approximately 22 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.

normal breathing during sleep

Partially Obstructed Upper Airway

Snoring – the symptom most commonly associated with OSA – 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.

obstructive sleep apnea airway diagram

Obstructed Upper Airway

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 OSA, 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 obstructive sleep apnea 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 apneato see their physician. Symptoms like excessive daytime sleepiness, poor concentration, poor memory, and even depression are common for people with obstructive sleep apnea.

Symptoms of Sleep Apnea

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 diagnostic testing:

  • Excessive sleepiness (use the Epworth Sleepiness Scale to evaluate your sleepiness)
  • Snoring (people with OSA usually snore but not always)
  • Witnessed apneas or irregular breathing during sleep (gasping, long pauses, etc – a spouse or partner may notice these)
  • Impaired concentration
  • Impaired memory
  • Morning headaches
  • Sexual dysfunction

Risk Factors for Obstructive Sleep Apnea

Physicians have identified a number of factors that may increase a person’s risk of having obstructive sleep apnea:

  • Obesity
  • Snoring
  • Family history of obstructive sleep apnea or snoring
  • Small upper airway (large tongue, large uvula, recessed chin, excess tissue in the throat and/or soft palate)

Heavier people 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 obstructive sleep apnea.

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.