Sleep apnoea is a medical disorder of varying clinical severity, which results from an involuntary cessation of breathing for a short time during sleep. Usually, this is a consequence of the muscles of the throat being completely relaxed and ‘obstructing’ or blocking the airway. This disorder is commonly referred to as obstructive sleep apnoea (OSA).
There are two types of breathing interruptions characteristic of OSA:
- Apnoea: where the muscles and soft tissues in the throat relax and collapse sufficiently to cause a total blockage of the airway; it’s called an apnoea when the airflow is blocked for 10 seconds or more
- Hypopnoea: a partial blockage of the airway that results in an airflow reduction of greater than 50% for 10 seconds or more
How can I tell if my sleep apnoea is severe?
The severity of sleep apnoea depends on how often your breathing is interrupted. As a guide:
- normal sleep: fewer than 5 interruptions per hour
- mild sleep apnoea: between 5 and 14 interruptions per hour
- moderate sleep apnoea: between 15 and 30 interruptions per hour
- severe sleep apnoea: more than 30 interruptions per hour.
There may be repeated apnoea episodes throughout the night, possibly one per minute or two in severe cases. You can’t breathe in oxygen or exhale carbon dioxide during the apnoeic event. This results in low oxygen levels and increased carbon dioxide levels in the blood. This alerts the brain to resume breathing and causes arousal. Each arousal sends a signal from the brain to the upper airway muscles to open the airway. Breathing is resumed, often with a loud snort or gasp. Frequent arousals, although necessary for breathing to restart, prevent restorative, deep sleep. This regularly disturbed sleep may cause tiredness and sleepiness during the day.
These conditions often go unrecognised and can severely disrupt people’s lives. As well as interrupting sleep, they are often linked with serious health problems such as high blood pressure, diabetes, heart disease and stroke. Excessive sleepiness can also increase the risk of motor vehicle and work-related accidents.
Types of sleep apnoea
There are two types of sleep apnoea:
- Obstructive sleep apnoea happens when your upper airway becomes blocked often while you sleep, reducing or completely stopping airflow. This is the most common type of sleep apnoea. Anything that could narrow your airway, such as obesity, large tonsils, or changes in your hormone levels, can increase your risk for obstructive sleep apnoea.
- Central sleep apnoea happens when your brain does not send the signals needed to breathe. Health conditions that affect how your brain controls your airway and chest muscles can cause central sleep apnoea.
symptoms
Symptoms are often worse when lying on their back in deepest sleep. A wide spectrum of symptoms falls under the umbrella of sleep apnoea.
Some of them are:
- Repeated short periods of snoring/noisy and laboured breathing where breathing is interrupted by gasping or snorting
- witnessed spells of apnoeas
- unrefreshing sleep leading to unexplained somnolence during daytime activities and work
- sleepy only when seated and relaxed, e.g. watching TV, but eventually sleepiness becomes so severe that car accidents and accidents in the workplace can occur
- Dry mouth on waking up caused by excessive mouth breathing
- waking headaches unexplained by other causes like migraine, dehydration, cluster headaches
- unexplained excessive sleepiness, tiredness or fatigue with the inability to concentrate on a particular task at hand (e.g. working on a computer or reading a book)
- nocturia (waking from sleep to urinate) unexplained by other urinary tract diseases like kidney disorders and prostate disorders
- choking during sleep with bouts of cough to clear the airway
- sleep fragmentation or insomnia
- cognitive dysfunction or memory impairment
- Frequent mood swings
- depression, short temper, grumpiness, personality change, and impotence in males, leading to a loss of interest in sex.
risk factors
In people with OSA, the airway has narrowed as the result of a number of factors, including:
- being overweight: excessive body fat increases the bulk of soft tissue in the neck, which can place a strain on the throat muscles; excess stomach fat can also lead to breathing difficulties, which can make OSA worse
- being male: it’s not known why OSA is more common in men than in women, but it may be related to different patterns of body fat distribution
- being 40 years of age or more: although OSA can occur at any age, it’s more common in people who are over 40
- having a large neck: men with a collar size greater than around 43 cm (17 inches) have an increased risk of developing OSA
- taking medicines with a sedative effect: such as sleeping tablets or tranquillisers
- having an unusual inner neck structure: such as a narrow airway, large tonsils, adenoids or tongue, or a small lower jaw
- Alcohol: drinking alcohol, particularly before going to sleep, can make sleep apnoea worse
- Smoking: you’re more likely to develop sleep apnoea if you smoke
- menopause (in women): the changes in hormone levels during the menopause may cause the throat muscles to relax more than usual
- having a family history of OSA: there may be genes inherited from your parents that can make you more susceptible to OSA
- nasal congestion: OSA occurs more often in people with nasal congestion, such as a deviated septum, where the tissue in the nose that divides the two nostrils is bent to one side, or nasal polyps, which may be a result of the airways being narrowed
How can I tell if I have sleep apnoea?
Screening yourself if you suspect OSAHS:
- Use the Epworth Sleepiness Scale (ESS) in the preliminary assessment of sleepiness.
- Consider using the STOPBANG Questionnaire as well as the Epworth Sleepiness Scale.
- Maintaining a sleep diary: you record your sleep patterns such as bedtime, number of hours slept, nighttime awakenings and awake time. You also can record your daily routine, naps and how you feel during the day.
If the self-screening tests reach a positive conclusion, you must visit your local GP, who would arrange for a referral to a pulmonary specialist (specialising in sleep disorders) for further detailed evaluation and treatment.
How to treat OSA and sleep apnoea?
There are a variety of treatments available for OSA that can help tackle symptoms.
Treatment options for OSA include:
- Lifestyle changes: Losing weight, reducing alcohol and smoking, and sleeping on your side can all help improve your OSA symptoms.
- Using a continuous positive airway pressure (CPAP) device: These devices are designed to prevent your airways from closing during sleep by delivering a continuous stream of compressed air through a mask
- Wearing a mandibular advancement device (MAD): This gum-shield-like device fits around your teeth and holds your jaw and tongue forward. This increases the space at the back of your throat while you sleep and improves OSA and snoring symptoms.
Surgery may be advised in severe cases or where it is thought that OSA is due to a physical problem, e.g. due to the inner structure of the neck. However, surgery isn’t suitable in many cases.
Are you concerned you may have sleep apnoea?
Sleep apnoea can profoundly affect your physical and mental well-being. It is important to contact your GP and the right specialists if you are struggling with your sleep or breathing. If left untreated or unchecked, sleep apnoea can cause other health conditions, such as strokes and hypertension. In severe cases, sleep apnoea can also lead to life-threatening conditions.
As a leading sleep and respiratory physician specialising in sleep apnoea and sleep-related breathing disorders, I offer consultations to diagnose and treat these conditions. Please contact me if you have any further queries about sleep apnoea or want further advice on the potential treatments available.
