Contrary to popular perception, snoring is not the exclusive preserve of the overweight, ageing male. About 15 million people in the UK snore and 30 per cent of them are women, says the British Snoring & Sleep Apnoea Association (BSSAA). What’s more, it is bad for their sex lives — in a study published today, the BSSAA has found that two thirds of people would make love more if their partner could stop snoring, while 70 per cent of couples affected by snoring sleep in separate bedrooms.

Snoring is caused by air turbulence hitting the structures in the mouth, nose and throat, making them vibrate. Women generally snore less than men because their airway is larger, so air can pass through unobstructed. It is also firmer, hence less likely to collapse. The number of women affected by snoring increases from the time of the menopause, though, suggesting a hormonal influence.

Dr Adrian Williams, a consultant respiratory and sleep physician at the Sleep Centre at St Thomas’ Hospital, South London, says that roughly 5 per cent of women snore before the menopause and about 15 per cent after it, loss of progesterone being the most likely reason for the increase. “Progesterone might stimulate the upper airway muscles,” he says. “It certainly stimulates breathing, so it protects against snoring.”

Dr Anita Simonds, a consultant in respiratory medicine at the Royal Brompton Hospital, Central London,is equally convinced that hormones play a part, but suggests that the menopausal decline in oestrogen — another respiratory stimulant — is to blame.

Yet another possible cause is hypothyroidism, a condition more common in women, especially post-menopause. A study at Manitoba University in Canada, published in the journal Sleep, shows a strong link between low thyroid hormone level, snoring and episodes of sleep apnoea (breathing stoppages during sleep).

Sleep apnoea is an exaggerated version of snoring in which the airway closes completely and breathing shuts down for ten seconds or more at a time. After an apnoea episode the brain automatically wakes the person up, usually with a gasp for air or a snort to kick-start breathing again, causing extremely loud and sudden bursts of snoring.

It is not only postmenopausal women who suffer. Some hormonal conditions, such as polycystic ovary syndrome, might cause young women to snore. “We have noticed an increased number of those patients being referred to us with snoring or sleep apnoea,” says Dr Simonds.

Hormonal changes in pregnancy can also prompt snoring when increased blood flow creates particular congestion in the nose and pharynx. When these swell, the resulting stuffiness forces the expectant mum to breathe through her mouth, leading to some gulping and snorting that generally disappears a few weeks after the birth.

“One of my patients had to be wheeled off to a side room in the postnatal ward because her snoring disturbed the other mums so much,” says Dr Simonds. “She told me later that the same thing happened when she had her last child, after which the snoring settled down until she hit the menopause.”

Dr Williams believes that another reason for snoring in pregnancy is that the enlarged belly pushes up the diaphragm, which in turn narrows the airway in the throat.

Being overweight is the most common cause of snoring in both men and women. It is closely followed by drinking alcohol, which relaxes the throat muscles and makes them more likely to collapse, and smoking, which leads to impaired breathing because of swelling, inflammation and catarrh in the nose and throat. Colds, allergies, nasal polyps or a damaged or crooked nose also make snoring worse, as does sleeping on your back.

A study by Professor Tim Spector and Dr Williams at St Thomas’ Hospital, published in Twin Research, found that genetic factors contribute substantially to various sleeping disorders, with snoring being one of the most heritable conditions. So you can blame your narrow airway, large tongue, large uvula and the snore- inducing shape of your soft palate on your parents.

TO STOP SNORING...

• Maintain your ideal weight
• Stop smoking
• Reduce alcohol intake at night and avoid sedative medicaments
• Eliminate allergens such as feather pillows, dust and pet hair
• Try anti-snoring products. These include nasal strips, homoeopathic nasal drops, nasal and throat sprays, decongestants
• Sleep on your side or raise the head of the bed by between 4in and 6in (10-15cm)
• Ask your dentist about anti-snoring dental appliances

  British Snoring & Sleep Apnoea Association, 52 Albert Road North, Reigate, RH2 9EL (01737 245638) www.britishsnoring.co.uk

  Sleep Apnoea Trust, 12a Bakers Piece, Kingston Blount, Oxon, OX39 4SW (0845 6060685) www.sleep-apnoea-trust.org

  British Sleep Society, PO Box 247, Colne, Huntingdon, PE28 3UZ www.sleeping.org.uk