Snoring can be infuriating if you are on the receiving end. But next time you feel forced to kick your partner out of bed for keeping you up all night (or take refuge in the spare room), bear in mind that anything more than an occasional snore could be a sign they need medical help.
Far from something to be brushed off, these nocturnal noises are rarely benign, writes the Daily Mail.
Typically, caused by a combination of physiology and environmental factors, snoring may - rather surprisingly - harm the body in a number of ways...
The constant vibration of habitual snoring causes damage and inflammation to the throat, and may be linked to thickening of the carotid arteries, which run up the sides of the neck supplying the head with blood.
This, say researchers at the Henry Ford Hospital in Detroit, increases the risk of artherosclerosis - furring of the insides of the blood vessels - and the chances of stroke.
Obstructive sleep apnoea (OSA) is a disorder that occurs due to the collapse of the airway in the throat during sleep and causes loud snoring and periodic interruptions in breathing. It has long been linked to heart disease and a range of other serious health problems.
The condition is thought to affect about five per cent of the adult population to some degree, with 250,000 Britons suffering what is deemed a severe form of it. However 25 million are thought to be habitual snorers, without OSA.
In the Henry Ford study, experts reviewed data for more than 900 patients, aged 18 to 50, who had been evaluated by the institution's sleep centre.
None of the volunteers suffered from OSA. They completed a survey regarding their snoring and had scans of their carotid arteries.
Compared to non-snorers, snorers were found to have significantly thicker arterial walls, an early sign of cardiovascular disease.
Surprisingly, those with high cholesterol, diabetes and those who smoked did not have thickened carotid arteries, leading the researchers to suggest that snoring was the biggest health concern for these people.
It Brings on Bronchitis
The same vibrations in the throat have been suggested as a factor in the development of chronic bronchitis, inflammation of lower airways accompanied by a persistent cough and the production of mucus or phlegm.
A Korean study found that individuals who snored six to seven times per week were 68 per cent more likely to develop the condition. The association was strongest in individuals who were overweight, but smoking was not a factor.
'Repeated snoring vibrations may act as mechanical stresses, leading to increased inflammatory response in the upper airway,' said the report.
Night-time acid reflux may be the cause of 'significant sleep impairment', including a sore throat, snoring and wheezing, according to one University of Arizona study.
Researchers discovered that half of those who suffer from diagnosed gastroesophageal reflux disease (GERD) - the medical term for long-term heartburn - reported sleeping poorly often or most of the time.
They suggested that ways to help reduce night-time reflux may include sleeping with the head and shoulders elevated, waiting between two and three hours after eating to go to sleep, and avoiding 'trigger' foods.
Expectant mothers who snore three or more times a week had a higher risk of poor delivery outcomes, including double the chances of a caesarean birth and two-thirds more likely to deliver a below-normal-weight baby, according to research from the University of Michigan Health System.
Those who started snoring during pregnancy had a higher risk of both elective and emergency C-sections than women who did not snore. Lowered levels of blood oxygen caused by interruption in breathing was suggested as a reason for this.
An earlier study from the same team showed that women who begin snoring during pregnancy are at high risk of increased blood pressure and pre-eclampsia.
Cures... but not for all
Patients diagnosed with OSA are offered a range of options.
The NHS recommends polysomnography, also called a sleep study, where brain waves, breathing, blood oxygen levels, heart rate and movements while asleep are recorded, followed by CPAP treatment.
This involves wearing a face mask at night to deliver air into the nose, or use of a 'mandibular advancement' device, which holds the jaw forward to keep airways open.
However, for habitual snorers, a GP may first simply suggest lifestyle changes: losing weight, avoiding alcohol, and giving up smoking.
Lifestyle habits such as drinking alcohol can cause the throat and tongue muscles to relax and fall back into the airway at night, blocking it.
In rare cases, a snore may be due to vibrations in excess tissues around the uvula, the soft part at the opening to the throat at the back of the mouth. There is limited evidence that surgery to reduce this tissue may help snoring, and due to lack of evidence it is not offered on the NHS.
But there is hope. A Brazilian study found that patients who snored without obvious cause (such as a cold) benefited from mouth and tongue exercises. These reduced the frequency of snoring by 36 per cent and loudness by 59 per cent.
Their exercises included:
• Pushing the tip of the tongue against the roof of the mouth and sliding the tongue backwards.
• Sucking the tongue up against the roof of the mouth.
• Forcing the back of the tongue against the floor of the mouth while keeping the tip of the tongue in contact with the lower front teeth.
• Elevating the back of the roof of the mouth and uvula by saying the vowel 'A'.
If the snore remains a problem, a referral to an ear, nose and throat (ENT) specialist may be the best way forward.