Sleep Disordered Breathing (SDB) is caused by a structural problem in the nasal passages or oral airway that hinders respiration during sleep. This structural problem is referred to as an obstruction. A nasal obstruction can be the result of swollen tonsils or adenoids, allergies, inflamed sinus membranes, an anatomically small airway, or a combination thereof. An oral airway obstruction occurs because of malocclusion, obesity (excess fat on the neck and chest), a hormonal imbalance/deficiency, pregnancy, an anatomically small airway, or a combination of thereof.

If the structural problem has its roots in the nasal passages, such as allergies or swollen sinuses, it is imperative to consult an otolaryngologist.

Otherwise, the oral airway must be examined. A normal airway remains patent during sleep. In other words, the airway retains its muscle tone even if the airway is completely relaxed. When a person suffering from Sleep Disordered Breathing falls asleep, the muscles in the airway relax, but then partially or fully collapse in on one another as the individual breathes in and out.

The sounds of snoring that a bed partner may hear are the result of pharyngeal tissues vibrating against one another. To sufficiently oxygenate the body, the air must force its way through the airway, partially or fully obstructed due to a loss of patency.

Gasping, choking or spasming and subsequent awakening is the body's reaction to loss of oxygen and is indicative of a complete obstruction of the airway.

Any obstruction of the airway is extremely detrimental to the intricate functioning of the cardiovascular, lymphatic, gastrointestinal, and nervous systems. SDB is divided into three subcategories, varying in severity: Snoring, Upper Airway Resistance Syndrome (UARS) and Obstructive Sleep Apnea (OSA).

Snoring is classified as the most moderate manifestation of a sleep disordered breathing problem. It is indicative of the onset or existence of a sleep disordered breathing condition. Snoring and the subsequent oxygen desaturation associated with it is believed to cause fetal retardation during pregnancy.

Upper Airway Resistance Syndrome (UARS) is marked by a partial loss of airway patency. Those who suffer from UARS are younger than the average OSA patient and are generally female. UARS is accompanied by gastroesophageal reflux, depression, bruxism, hypothyroidism, and asthma. Those whose problems are diagnosed as more severe than UARS but less severe than OSA may experience apneas and hypopneas as well.

Obstructive Sleep Apnea is characterized by repeated episodes of cessation in breathing for at least 10 seconds at a time called apenic events . Composed of apneas and hypopneas, the cessation of breathing and subsequent oxygen desaturation accompanying it.This is indicative of a complete loss of airway patency (muscle tone).

Patients demonstrate inspiratory flow levels while asleep that are 50% less than inspiratory flow levels while awake.