Mr Oko’s Guide to Sleep Apnoea
Around 20% of the population snore, but only about 4% have sleep apnoea — and around 180,000 people in England have severe sleep apnoea.
Snoring is caused by turbulent airflow in the upper airway (the nose and throat). This turbulence generates the noise, and can also collapse the airway. It is best thought of as a spectrum, with mild snoring at one end and severe obstructive sleep apnoea at the other. The clinician’s challenge is to find where you sit on that spectrum and the right treatment for you.
Common symptoms
Loud snoring
Breath holding at night (apnoea) or choking during sleep
Dry mouth on waking
Daytime fatigue and low energy — sometimes falling asleep during mundane activities
Multiple trips to urinate during the night
Early morning headaches
Loss of interest in sex
Short-term memory loss
Mood swings and a short temper
The risks of untreated sleep apnoea
Untreated severe sleep apnoea is strongly associated with:
Heart attacks
Stroke
Hypertension
Diabetes
Memory impairment
Depression
Early mortality
Road traffic accidents
The increased tiredness can cause problems in day-to-day life — when concentrating or driving, for example. Research into the full extent of the health risks is ongoing, but sleep apnoea has been linked to an increased risk of diabetes, high blood pressure, stroke and serious heart problems.
People with sleep apnoea are around 7–12 times more likely to be involved in a car accident, and may find their concentration limited during the day. Treating the condition can reduce the chance of accidents by over 80%.
Types of sleep apnoea
Obstructive sleep apnoea (OSA)
When you sleep your body relaxes all of your muscles, which can obstruct airflow and disrupt your breathing. This is the most common form of sleep apnoea and can be treated relatively easily. Those most at risk are overweight with low muscle tone around the neck, or have facial features that make obstruction more likely, such as an undershot jaw.
OSA is classified as mild (5–15 episodes per hour), moderate (15–30) or severe (more than 30). Obstructive sleep apnoea syndrome is diagnosed from a combination of an elevated Epworth score (above 10) and evidence of breath holding or desaturation on a sleep study.
Central sleep apnoea (CSA) or Cheyne-Stokes respiration
A much rarer form that happens when nerve signals from the brain are delayed, making breathing irregular. It indicates a problem in the central nervous system, but can be treated with drugs that manipulate the brain’s need to take in oxygen. Rather than struggling for breath, an episode of CSA is a few seconds with no effort to breathe at all.
Mixed sleep apnoea (MSA)
An overlap of CSA and OSA. Treatment can help to ease it, but cannot remove the problem completely.
How is obstructive sleep apnoea diagnosed?
Tests to confirm OSAS
If you have symptoms that suggest sleep apnoea, or a high score on the Epworth Sleepiness Scale, your GP may refer you to our clinic for tests carried out while you sleep. The tests used may depend on local policies and available equipment, for example:
The oxygen level in your blood can be monitored by a probe clipped onto your finger.
Your breathing can be recorded using special belts around your chest and abdomen, along with your pulse rate and oxygen saturation.
A video of you sleeping may also be helpful.
You may be asked to spend a night in hospital, though some tests can be carried out at home using equipment supplied by our specialists.
The results help us firmly diagnose or rule out sleep apnoea. We will also check your blood pressure and may suggest other tests to exclude other causes of sleepiness — for example, a blood test for an underactive thyroid gland.
Epworth Sleepiness Scale
If you experience daytime tiredness, a questionnaire can measure where you are on the Epworth Sleepiness Scale. It gauges how sleepy you feel during the day; a high score suggests you may have a sleeping disorder.
Visilab
Visilab is our in-house hospital system for video-recording your sleep through the night. It takes place in a comfortable room within the sleep clinic, and any disturbances during the night are recorded and analysed — a very in-depth way to assess your sleep problem.