What is happening during sleep

Obstructive sleep apnoea is far more than loud snoring. It is caused by collapse of the upper airway, the passage between the nose and throat and the main airway, which happens as the muscles relax in sleep. The closure makes oxygen levels drop and briefly wakes the sleeper; the brief awakening opens the airway again and restores oxygen levels. It is these repeated arousals and brief awakenings that break up sleep and cause daytime sleepiness and the other symptoms.

How it shows up

The airway repeatedly closes during sleep, leading to broken sleep, morning headaches and daytime sleepiness. Patients may also have fatigue, and subtler symptoms such as poor concentration, reduced libido and mood changes. Bed partners notice snoring, gasping and, in some cases, episodes in which breathing stops (apnoeas).

Many patients do not realise they have any symptoms at all, because OSA develops over years and people habituate to it. Many only realise how much they have been suffering after successful treatment relieves their symptoms.

Who is at risk

Obesity, a large neck, a small or recessed jaw and enlarged adenoids can all contribute to OSA. Heavy alcohol intake, male sex and advancing age are also significant risk factors. However, in a significant number of patients none of these risk factors are present. Wearables such as smart watches now track sleep quality to varying degrees and can pick up disturbed sleep, but a formal clinical sleep study is needed to diagnose OSA.

The risks of leaving it untreated

Left untreated, it raises the risk of high blood pressure, heart disease, stroke and road accidents, and it can affect mood and memory. Untreated OSA has been linked to heart disease, stroke, depression and diabetes, and patients with untreated OSA have a higher risk of complications when they undergo general anaesthesia for routine surgery. Patients with OSA are often quoted as having three times the risk of an accident while driving, and working with heavy machinery can be very dangerous for those with severe symptoms, so treatment is often essential for these reasons alone.

How it is diagnosed

A sleep study makes the diagnosis. Sleep studies range from hospital-based studies to home-based devices that patients set up themselves, and in most cases OSA can be diagnosed with a simple, cost-effective home sleep test. Severity is measured by indices such as the apnoea–hypopnoea index (AHI), which counts how often breathing stops or becomes shallow each hour, together with how far and for how long oxygen levels drop. These indices determine the severity of OSA and the decision on treatment.

CPAP and other treatments

CPAP, a gentle flow of air delivered through a mask, remains the mainstay of treatment, and getting the right mask and support makes all the difference. CPAP (continuous positive airway pressure) blows air through the nose or mouth to keep the upper airway open during sleep, acting as a pneumatic splint so that oxygen levels do not drop.

The idea of sleeping with a machine is a big barrier for many patients. The noise, the discomfort of wearing a mask and the prospect of long-term treatment can be daunting, and machines and masks can now be bought online without any clinical assessment or oversight. But mask fitting, machine selection and pressure setting are both a science and an art, and skilled, experienced sleep technicians are vital to starting patients off correctly. Long-term adherence to treatment can only be achieved if this first step is done well.

Weight loss, sleeping position, oral appliances and sometimes surgery all have a place. In mild OSA, or in those with minimal symptoms, weight loss, changes in sleeping position and oral appliances may offer some benefit, but for moderate to severe OSA, CPAP remains the gold standard. Surgery is only indicated in a very small, selected group of patients and remains second line, because outcomes are mixed.

What to expect

With the right treatment and support, restful sleep and waking refreshed are realistic goals.

Lung and Respiratory Conditions: A Patient Guide · The Aeden Physicians

Frequently Asked Questions

What are the symptoms of obstructive sleep apnoea?

Excessive daytime sleepiness, morning headaches and fatigue are typical, with subtler signs such as poor concentration, reduced libido and mood changes. A bed partner may notice snoring, gasping or pauses in breathing.

What happens if sleep apnoea is left untreated?

Untreated OSA has been linked to heart disease, stroke, depression and diabetes. Patients with untreated OSA also have a higher risk of complications when they undergo general anaesthesia for routine surgery.

How is sleep apnoea diagnosed and treated?

A sleep study makes the diagnosis, and in most cases a home sleep test is enough. CPAP, a gentle flow of air delivered through a mask, remains the mainstay of treatment; weight loss, sleeping position, oral appliances and sometimes surgery all have a place.