Obstructive Sleep Apnea(OSA) occurs when the muscles at the back of the throat relax too much to allow normal breathing. Structures like soft palate, the uvula(which is a triangular tissue that hangs from the soft palate), tongue and the tonsils are supported by the muscles at the back of the throat. These TMJ muscles, when they relax the airway narrows or closes. When one breathes in and out there is often disrupt in breathing for 10 to 20 seconds. This leads to the lowering of oxygen and increase in the level of carbon-dioxide in the blood.
Any obstruction in the airway is virtually a cause for OSA. These obstructions can be in the upper airway(nose and mouth). Nasal blockages like nasal polyp, deviated nasal septum, bulbous conchae, allergic rhinitis, adenoids, tonsils. Oral blockages - large tongue size, Malampati position of the tongue, tongue tie, narrow dental arches, posteriorly displaced jaw. The other blockages can be caused due to excessive neck fat, faulty neck position, pharyngitis etc.
The brain can sense the disturbance in breathing and sends signals to wake up from sleep for a brief moment so that the airway can be opened up again to allow normal breathing. This brief moment of awakening in sleep is often forgotten by one.
By awakening, one can take a deep breath or normal breath which is revived and made up for the breathing disturbance. People often make a Snoring, choking and gasping sound as a result of this breathing disturbance. This can get repeated over and over again in sleep as many as than thirty times in an hour and continue all night. This may happen recurrently every night to affect one's sound sleep and impairs the ability to complete desired sleep which makes one feel sleepy during odd hours of the day. It may also happen that people suffering from sleep apnea may not recognize that they suffered from sleep or breathing disruption and think that they slept well all night.
In adults, the most common cause of sleep apnea is obesity and excess weight. The muscles of throat and tongue are more relaxed during sleep. The soft tissue causes the airway to block. Hypertension, alcoholism, high blood pressure and hypothyroidism are also related to Obstructive Sleep Apnea.
In children, sleep apnea can be caused due to childhood obesity, enlarges tonsils and dental conditions such as an overbite. Birth defects such as Down's syndrome or Pierre-Robin syndrome may also lead to this problem.