Snoring: Causes, When It Is Sleep Apnea and What Helps

This article focuses on the decisions facing a person who snores, or their partner: is it still ordinary snoring, when to get tested, what actually reduces snoring and which methods are supported by guidelines. A full description of the symptoms and diagnosis of sleep apnea is in our article on sleep apnea symptoms and diagnosis, and an overview of treatments other than CPAP is in a separate text on CPAP alternatives — we do not repeat that material here.

The text is educational. It does not replace a medical examination, and one note matters especially for people with heart disease or hypertension, or who drive professionally — in them a suspicion of apnea should be clarified sooner.

While awake, throat muscles keep the airway open. In sleep, especially in deeper stages and in REM, the tone of those muscles falls, and the tongue and soft palate tend to drop backwards. Air flows through a narrower channel at higher speed, which sets the soft tissues vibrating — that is what we hear as snoring. The narrower the throat and the floppier the tissues, the louder the sound.

Snoring and obstructive sleep apnea lie on one continuum: in snoring the airway narrows but air still flows; in apnea the throat walls collapse enough that flow stops or falls markedly, and the body reacts with a brief arousal and a drop in blood oxygen. We describe this mechanism in detail in our entry on obstructive and central sleep apnea. This is why you cannot always tell from the sound alone which side of the boundary you are on — loud snoring often accompanies apnea, but some people with apnea snore little.

Airway narrowing is contributed to by anatomical factors (a recessed or small jaw, a large tongue, a long palate, enlarged tonsils, a deviated septum), peripheral factors (fat deposition around the neck) and functional ones (a blocked nose that forces mouth breathing and lowers the tongue). A combination of several usually explains why one person snores and another does not.

The second layer consists of factors that change from day to day or year to year and that can be modified. The best documented among them are alcohol and body weight.

The mechanism is simple: alcohol further relaxes the throat muscles and dampens the arousal response to obstructed breathing, so the same anatomy that breathes quietly after a sober night may snore loudly after an evening of drinking. For this reason the first test in a person who snores is often a simple question: is the snoring clearly worse after an evening with alcohol? We write more on alcohol's effect on the structure of the night in a separate article on alcohol before bed.

The simplest screening tool is the STOP-Bang questionnaire, made up of eight yes/no questions: S (Snoring) — loud snoring; T (Tired) — daytime tiredness or sleepiness; O (Observed) — observed pauses in breathing; P (Pressure) — high blood pressure; B (BMI) — body mass index above 35; A (Age) — over 50 years; N (Neck) — neck circumference above 40 cm; G (Gender) — male sex. Each yes counts 1 point.

How to read it in practice? A score of 0-2 suggests low risk of apnea, 3-4 intermediate risk, and 5 or more high risk. A score of 3 or more is the threshold that picks up people with apnea well (high sensitivity), at the cost that some people with a positive result do not have apnea. A positive result is therefore a reason for testing (polysomnography or home polygraphy — see our entry on polysomnography), not a diagnosis. A negative result with ongoing symptoms should not be reassuring if daytime sleepiness or observed breathing pauses persist.

For people without diagnosed apnea it makes sense to proceed from the cheapest and safest methods to more invasive ones. Below is a summary with an assessment of how well each is supported by data.

People whose work involves the safety of others (professional drivers, train drivers, pilots) should not delay diagnosis — sleepiness at the wheel is a direct danger. A limitation of this article is that it does not cover snoring in children, in pregnancy or in neurological disease — those situations need separate assessment.

A good approach to snoring has two steps. First settle whether it is just a sound or a symptom of apnea — STOP-Bang and, where needed, a sleep study do that. Only then choose a method: begin with what costs least and has the best data (alcohol, body weight, sleeping position, nose), and consider a dentist-fitted appliance when lifestyle changes are not enough. Avoid ready-made solutions that promise more than the studies say.