Snoring is the sound that is produced when air flows past relaxed tissues in the throat, causing the tissues to vibrate as a sleeping person breathes. According to the Canadian Society of Otolaryngology — Head and Neck Surgery, 45 percent of adults snore at least occasionally and 25 percent snore habitually. While it’s normal for everyone to snore now and then, chronic snoring can be an indication of an underlying condition, such as obstructive sleep apnea (OSA). There are a number of other factors that are known to contribute to snoring, including a person’s anatomy and lifestyle habits.

What causes snoring?

Obstructive sleep apnea (OSA)

Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder, estimated to affect 3% to 7% of adult males and 2% to 5% of adult females in Western countries. People with obstructive sleep apnea experience periods of interrupted or halted breathing during sleep when muscles in the head and neck relax, causing surrounding tissues to press on the windpipe and hinder the flow of air.

Snoring is one of the main symptoms of obstructive sleep apnea — but while many people with OSA snore, not everyone who snores has OSA. Other symptoms of OSA include snoring that starts with a loud sound when breathing resumes, falling asleep frequently during the day, and morning headaches.

Continuous positive airway pressure (CPAP) therapy is widely used in the treatment of OSA. CPAP therapy involves the use of a machine (usually with a hose and mask attachment) to deliver a steady flow of air to the user as they sleep, keeping the airway open and promoting normal breathing. In addition to lowering the risk of long-term health issues linked to obstructive sleep apnea, CPAP therapy can also alleviate snoring in those with OSA, as the air pressure helps to keep airways free of anatomical blockages.

Nasal congestion

During sleep, the body naturally tries to breathe through the nose. However, if a person has a congested or stuffy nose, they may be forced to breathe through their mouth while they’re asleep. This encourages the muscles in the back of the throat to relax, and the subsequent narrowing of the airway can lead to snoring.

Allergies and infections with symptoms that affect the nose and throat can often result in nasal congestion. Congestion related to illnesses (like a cold or the flu) typically passes within one to two weeks, while nasal congestion associated with allergies may persist over a longer period of time if left untreated. Treatment options for snoring brought on by nasal congestion differ depending on the cause but may include nasal decongestants, nasal steroids, or oral antihistamines.

Head and neck anatomy

Some people may be more predisposed to snoring due to their anatomy. A deviated septum occurs when the septum (the cartilage and bone that divides the nasal cavity) is off-centre. Nasal passages can become obstructed or narrowed as a result of septum deviation, and those with deviated septums may be more likely to snore because of this. Having an enlarged tongue or tonsils is also believed to contribute to snoring, as the vibrations that produce the sound of snoring can increase and airflow can be obstructed.

For individuals whose snoring is linked to their anatomy, treatment approaches are available — such as dental devices — that aim to promote the inward and outward flow of air during sleep.

Excess weight

Research has shown that obese people have an increased likelihood of experiencing snoring. This is typically due to the presence of neck fat — it compresses the upper airway when a person lies down, which can result in snoring. Overweight people are also more likely to have extra tissue in the back of their throat, which can fall toward the airway and hinder the flow of air. Additionally, excess abdominal fat can push a person’s diaphragm up as they sleep, compressing the ribcage. This puts pressure on the lungs, which can restrict airflow.


A number of sleep-related changes happen as a person grows older. The tongue and the muscles around the airway may weaken with age, meaning older adults may be more likely to snore. One study examining the prevalence of snoring in older adults found that 33% of male participants and 19% of female participants reported loud snoring.

Alcohol and sedative medications

Alcohol and sedative medications may relax the muscles that support tissues around the airway, which can lead to snoring. The epiglottis — a flap of cartilage that serves as a gateway between the throat and the mouth — can be affected by alcohol, and throat muscles may become more constricted in people who have been drinking alcohol. The effect of alcohol on snoring is thought to be more pronounced in those who are already prone to snoring.


Smoking cigarettes can cause inflammation in the tissues of the upper airway, which restricts airflow and spurs the production of extra mucus. A narrowed upper airway, congestion, and post-nasal drip are believed to contribute to snoring in smokers.

A 2004 study found that habitual snoring was more prevalent among current smokers and ex-smokers than in people who had never smoked. Snoring was also more common in non-smokers who were exposed to passive smoking at home on a daily basis than in those who were never exposed to passive smoking in their homes. Along with the multitude of other health benefits that come with smoking cessation, quitting smoking may also help to alleviate snoring.

Sleeping position

Snoring tends to happen more often when a person is sleeping on their back. In this position, the tongue and soft palate can fall to the back wall of the throat, causing vibrations that result in snoring. A side-sleeping position can reduce the compression of airways and may help to alleviate snoring.

Although occasional episodes of snoring are normal, chronic snoring — or snoring that is accompanied by periods of interrupted breathing — can be an indicator of an underlying health condition, and should be discussed with a doctor.