snoring

Why does anyone snore?

The upper airway region (nose, mouth, and throat above the larynx) is collapsible to enable us to talk and swallow. More than than 30 pairs of muscles control the degree of openness of the airway in a process of balancing the natural tendency to collapse with the need to maintain an open airway. Snoring sounds are produced when these relaxed tissues vibrate with airflow ("flap in the breeze" if you will¹). Certain structural abnormalities - enlarged adenoids or tonsils, abnormalities of facial bone structure, or obesity can disrupt this balance in the direction of more easy obstruction of the airway and hence more noisy breathing.

During deeper, non-REM sleep (when we are not dreaming), breathing is regular but more shallow. There is marked relaxation of the muscles in the upper airway region, which causes increased resistance to airflow in the upper airway and may produce snoring sounds. When we dream, the the muscles of the upper airway relax even more. Breathing is more erratic with regard to rate and depth. There are frequent pauses, and snoring may be more pronounced.

Snoring in children is a common complaint of parents. About 12% of normal children snore to some degree during childhood. The snoring may not be indicative of underlying problems with nighttime respiration, but it is potentially a sign of more serious underlying disease - obstructive sleep apnea. While most children who snore do not have obstructive sleep apnea, it must nevertheless be considered as a possibility for every child who snores.

¹ My personal theory is that snoring is always associated with some degree of abnormal upper respiratory tract obstruction. The noise is produced by vibration of the soft tissues in response to increased velocity of airflow through the narrowed regions of the upper airway. This increased velocity is caused by the fact that a given volume of air pushed through a narrowed passage in a given time must automatically flow faster - Bernoulli's principle. The faster flow produces lowered local airway pressure, and this produces in term a fluttering effect of the tissues. A very similar mechanism lies at the root of the characteristic barking cough of croup.

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