Obstructive sleep apnoea (OSA) arises when throat muscles and soft tissue relaxes, narrowing the airway, and impairing normal breathing.5 NHS Choices describes two types of OSA:14

·       apnoea €“ the airflow is totally blocked for 10 seconds or more;

·       hypopnoea€“ a partial blockage reducing airflow by more than half for 10 seconds or more.

Central sleep apnoea (CSA) is rarer and arises when the brain does not signal properly to the breathing muscles during sleep, or there is a weakness in breathing muscles.14,15

Reduced oxygen and build-up of carbon dioxide in the blood triggers the brain to pull the sleeper out of deep sleep or even wake the person up (but not necessarily so that they are aware of the OSA), so that the airway regains its form to allow airflow again. This disturbed sleep means the person will not feel refreshed the next morning.

Airway narrowing in OSA is associated with several factors:14

·       being overweight €“ with body bulk pressing on the airways in the neck and lungs;

·       males are more likely than females to have OSA;

·       getting older €“ anyone can experience OSA, but it is more common in people aged over 40;

·       having a neck collar size of 17 or higher (43cm+);

·       anatomy of the mouth, throat and airways;

·       going through the menopause, with hormones relaxing the throat muscles more than usual;

·       a family history of OSA;

·       nasal congestion, eg due to a divided septum or polyps;

·       smoking, alcohol and some medication, notably tranquilisers.

Almost 4 million people have OSA to some degree: up to 4 per cent of middle-aged men, 2 per cent of middle-aged women, and 15-20 per cent of people aged over 70 may be affected. However, an estimated 80 per cent of people with OSA have not yet been diagnosed.4

Treatment includes addressing the factors outlined above, as well as recommending sleeping on one's side or semi-propped up. Gum shield-type devices can reduce snoring.16

However, the Sleep Apnoea Trust says: €The only really effective treatment currently used for bad sleep apnoea is continuous positive airway pressure (CPAP).€ This involves the patient wearing a small mask over the nostrils (or mouth), with an air pump working while asleep to keep the airways open. Surgery is considered a last option.