Sleep disordered breathing occurs when there is restriction of breathing during sleep, typically caused by tissue collapse in the throat (or pharynx, see the adjacent picture in the upper blue areas). The main sites of collapse during sleep are in the oropharynx (the soft palate, tonsils, and upper base of tongue) or the hypopharynx (the lower base of tongue and epiglottis).
Snoring occurs when the tissues collapse enough so that they vibrate during sleep, but not enough to cause a reduction in breathing (hypopnea) or a complete cessation of breathing (apnea). There are no drops in the oxygen levels in the blood or arousals. Snoring is a nuisance!
Sleep apnea occurs when the tissues collapse enough so that they cause reduction in breathing (hyponea) and complete cessation of breathing (apneas) for a specific period of time, as well as a drop in the oxygen levels in the blood. This not only causes the low oxygen levels, but patients with sleep apnea also repeatedly arouse (wake up) because of the apneas and hypopneas. Patients often awaken feeling unrefreshed from sleep, feel tired throughout the day, and feel the need (and sometimes do) fall asleep at inappropriate times. Sleep apnea can also cause neurocognitive, heart, lung, vascular, endocrine, and kidney problems. Untreated sleep apnea is a health hazard!!
The external nose includes cartilage and bone that work together for both form and function, including the nasal bones, upper lateral cartilages, and lower lateral (or alar) cartilages. Inside the external nose, the septum and turbinates are important structures that help to compartmentalize the nose and to prepare the air we breathe during inhalation.
Nasal obstruction results from anatomic problems externally (for example weak cartilages that collapse too easily) anatomic problems internally (for example septal deviation) or from inflammatory problems (chronic rhinitis, sinusitis, or nasal polyps).
When nasal breathing is poor, it significantly affects breathing during sleep. On one hand, it may cause individuals to be mouth breathers, which leads to worsening collapse in the throat. On the other hand, some patients will continue to breathe through the nose, despite increased resistance from some of the above factors, which causes a greater amount of collapse in the throat.