Snoring: Causes & Effects

Snoring occurs when the sleeper's airway is constricted and the air that moves in and out during breathing causes parts of the nose, mouth and throat to vibrate, producing noise. The noise ranges from soft whistling or wheezing sounds to loud, sudden snorts and can indicate serious breathing problems that disturb sleep.

At the very least, many people are embarrassed by the noise they make, and snorers who sleep with other people often find their bed partners complaining about diminished rest due to loud snoring sounds. The chance of snoring increases with age, but even children can experience episodes of snoring due to temporary blockages in the nose or throat.

The National Sleep Foundation estimates that of the 90 million American adults who snore periodically, 37 million do it habitually. Men are more likely to snore than women, and overweight people snore more often than others, but anyone can be affected. In addition to the physical condition inducing the snoring, snoring can indicate the presence of a serious condition called sleep apnea, or pauses in breathing during the night.

The flow of air in snoring is described as turbulent, or chaotic and highly irregular, a characteristic that increases the amount of physical vibration and thus fosters the production of sound.

Physical Structures Involved in Snoring

The nose is the body's first choice of passageways through which to breathe. It has two hollow sides (the nasal cavity) divided by the septum, which is an anatomical term for such a partition. The nasal septum is thin and constructed of cartilage, lending itself to vibration.

If the nasal septum is not straight (which is true for most people) or evenly balanced, that condition is called a deviated septum. If the crookedness of the septum is pronounced enough to block the nose, then snoring will, of necessity, occur as air is forced past that obstruction. A deviated septum can be congenital, or it can be caused by damage to the nose.

The turbinates are small, bony prongs inside the nose, three on either side, that are covered with mucous membranes and help prepare incoming air (by filtering, warming, and so on) to make it suitable for the lungs to breathe. They can vibrate in their own right, and they also contain blood vessels that swell and contract, so room for airflow naturally shifts from side to side of the nose during sleep.

If the turbinates' swelling on one side does not abate sufficiently before the other side swells, that can cause snoring by blocking the nose. Other types of blockage result from allergies that swell nasal tissues, the swelling and drainage experienced in colds or sinus infections, or enlarged adenoids (which consist of lymphatic tissue between the nose and the back of the throat).

Blockage of the nose means air must then come in through the mouth, which contains a number of structures prone to vibration and so leads to increased snoring noise. The soft palate (or velum, which is the Latin word for "sail") is a piece of muscular tissue hanging down from the roof of the mouth at the back, between the mouth and the nasal passages. Its shape, position, and texture make it ideal for vibrating.

There is disagreement as to whether the uvula, which is a piece of soft tissue attached to the soft palate, plays a role in snoring. Some specialists insist it does vibrate, and sometime recommend its removal to address snoring, while others say such surgery is not only unnecessary but also does nothing to correct the problem.

The tonsils, or palatine tonsils, are visible on either side of the throat, at the back, and their function is to ward off infections. When they become infected and enlarged, they sometimes fail to shrink thereafter. If that happens, there is less space for air to pass, and more snoring results.

The tongue can also obstruct the airway if it is large enough at the back to occupy part of the throat's space, or especially if it slips backward into the throat. A study published by the American Thoracic Society shows that fat deposits next to the pharynx (the part of the throat just behind the mouth and nasal cavity) cause not only snoring but also obstructive sleep apnea.

Growths like cysts, tumors, or nasal polyps, which are masses that form on the mucous membranes lining the nose and sinuses, can also trigger snoring.

Causes of Snoring

Relaxed Muscles

The importance of muscle relaxation in snoring cannot be overstated. Relaxed throat muscles, or a floppy tongue, can easily fall together or slip out of place, blocking the throat. That is why substances that relax muscles, including alcohol and some drugs, promote snoring. In fact, any drug prompting deep sleep promotes snoring.

In REM (dreaming) sleep, the muscles lose tone completely, which means they relax. Thus, snoring is often a sign that a sleeper is in the REM stage of sleep. Age causes a permanent loss of muscle tone in the throat, which is why older people in general are more prone to snoring.

Throat Weakness

Weakness of the throat muscles that causes the throat to close during sleep is more serious, and there are many diseases of the muscles that can cause this condition and thereby encourage snoring. Some of these are muscular dystrophy, myasthenia gravis, and amyotrophic lateral sclerosis (ALS), which is also known as Lou Gehrig's disease. If you have one of these illnesses, any snoring produced will of course be a very minor consideration in contrast with the gravity of the condition.

Jaw Problems

A jaw that is disproportionate in size or oddly positioned in relation to the configuration of the mouth, nose and throat jaw may be prone to muscular tension, which can hold the mouth open and make structures in the mouth and throat more likely to vibrate. If the lower jaw relaxes and slips backward in the night, that can narrow the airway and cause snoring.

Position During Sleep

Sleeping on one's back can lead to snoring even in people not otherwise likely to snore, because it frequently results in the tongue dropping to the back of the mouth, or causes gravity to act on relaxed muscles by pulling them down, obstructing breathing. Remember, gravity plus loose muscles frequently equals blocked airway.

Gaining Weight

Adding fatty tissue around the throat is a frequent cause of snoring, and the more Americans tend to obesity, the more they snore. A hereditary predisposition to deposition of fatty tissue in the neck area just makes it worse, and if you are thin but notice a small pad of fat under your chin, or you have a neck that is relatively large in circumference to begin with, you should avoid putting on weight if you wish to fend off snoring.

One doctor has established a handy quick classification of the causes of snoring. Snoring is caused either by (1) inherited physical characteristics of the nose, mouth, lower jaw, and airway that predispose a person to snore, (2) alcoholism, drug use, or illness that results in relaxed muscles, (3) obesity, or (4) obstructive sleep apnea.

Effects of Snoring

Normal snoring, called primary snoring, is harmless to the snorer (although annoying to anyone who sleeps with that person), but snoring caused by OSA, while not harmful in itself, signals that the patient needs medical treatment for the OSA. But if your snoring is the primary type, you are in luck, medically speaking.

In fact, the primary snorer often does not know he snores until someone else mentions it. There are countless tales of people in the military who must sleep in rooms full of other people and find themselves in the unwanted company of someone who snores, who is often shocked to learn about the snoring. The snorer also learns that the noisy habit is not a method of gaining popularity.

In such a circumstance, those annoyed by the snores are a captive audience, but the situation changes when the one annoyed is a valued bed partner. The bed partner is often the only one who suffers from the snoring, and when snoring is sufficiently severe that it prompts the bed partner to seek other space at night in order to sleep, that is the point at which many snorers begin to consider the habit a problem.

To learn how to treat snoring, see our page on how to stop snoring.