Are you dying for a good sleep?
If you or your partner have sleep apnoea, can it can also be the case, you don't even know it. But it's more than just a sleep annoyance problem - it’s medically linked to increased chances of diabetes, heart disease and other conditions, and it can put your life at risk...!
Sleep is marked by dynamic changes throughout the body. It’s made up of different phases, and as you move through them, your breathing, blood pressure and body temperature will all fall and rise. Tension in your muscles mostly stays the same as when you are awake – except during REM phases, which account for up to a quarter of your sleep. During these, most major muscle groups ease significantly. But if your throat muscles relax too much, your airway collapses and is blocked. The result is obstructive sleep apnoea – from the Greek ápnoia, or "breathless".
With sleep apnoea, your air supply is continually interrupted, causing blood oxygen levels to plummet. You then stir, gasping, trying to breathe. This can happen hundreds of times a night, and the ill-effects are many and severe.
Apnoea itself puts puts massive load strain on the heart, as it races to pump blood more quickly to compensate for the lack of oxygen. Fluctuating oxygen levels also cause plaque to build up in the arteries, increasing the risk of cardiovascular disease, hypertension and stroke. In the mid-1990s, the US National Commission on Sleep Disorders Research estimated that 38,000 Americans were dying every year of heart disease worsened by sleep apnoea.
Clinical evidence on sleep apnoea
There’s also growing evidence that the condition affects glucose metabolism and promotes insulin resistance – leading to type 2 diabetes – and encourages weight gain.
Then there’s the exhaustion of never having a full night’s sleep, which is associated with memory loss, anxiety and depression. Lack of sleep also causes inattention that can lead to traffic accidents. A 2015 study of drivers in Sweden found that those with sleep apnoea are 2.5 times more likely to have an accident than those without. It also fuels absenteeism, and people with apnoea are fired from their jobs more frequently than those without.
One study found that people with severe sleep apnoea were, all told, three times as likely to die during an 18-year period as those without.
The hidden side of apnoea
But, as with smoking during the first decades after it was discovered to be lethal, there’s a disconnect between the harm that the condition causes and the public’s perception of it as a threat. “They fail to link sleep apnoea with its many serious co-morbidities,” says a report commissioned by the American Academy of Sleep Medicine, which estimates around 12% of its population suffer silently – but an alarming 80% go undiagnosed. This prevalence is also found globally: nearly a billion people in the world suffer from the condition according to a 2019 study.
Research is now scrambling to catch up with this largely undiagnosed killer. Medical science has been working overtime to find a solution, from in-depth studies of hypoxia – how the body reacts to lack of oxygen – to new types of surgeries and appliances for treating the condition. Of the billion or so people across the globe struggling with sleep apnoea – most probably not even aware of it, never mind receiving treatment.
While there are enduring risk factors for sleep apnoea – such as obesity, a large neck or large tonsils, a small jaw, or getting older – it doesn’t present itself until after an individual falls asleep. The only way to diagnose it is to monitor someone’s sleep.
Obstructive Sleep Apnoea
Or just (OSA) is defined as the cessation of airflow during sleep preventing air from entering the lungs caused by an obstruction. These periods of 'stopping breathing' only become clinically significant if the cessation lasts for more than 10 seconds each time and occur more than 5 times every hour. OSA only happens during sleep, as it is a lack of muscle tone in your upper airway that causes the airway to collapse. During the day we have sufficient muscle tone to keep the airway open allowing for normal breathing. When you experience an episode of apnoea during sleep your brain will automatically wake you up, usually with a very loud snore or snort, in order to breathe again. People with OSA will experience these wakening episodes many times during the night and consequently feel very sleepy during the day: they have an airway that is more likely to collapse than normal.
How Do I Know I Have Sleep Apnoea?
People with sleep apnoea may complain of excessive daytime sleepiness often with irritability or restlessness. But it is normally the bed partner, family or friends who notice the symptoms first. Sufferers may experience some of the following:
- Extremely loud heavy snoring, often interrupted by pauses and gasps
- Excessive daytime sleepiness, e.g., falling asleep at work, whilst driving, during conversation or when watching TV. (This should not be confused with excessive tiredness with which we all suffer from time to time)
- Irritability, short temper
- Morning headaches
- Changes in mood or behaviour
- Anxiety or depression
- Decreased interest in sex
Remember, not everyone who has these symptoms will necessarily have sleep apnoea. We possibly all suffer from these symptoms from time to time but people with sleep apnoea demonstrate some or all of these symptoms all the time.
Diagnosing Sleep Apnoea
OSA can range from very mild to very severe. The severity is often established using the apnoea/hypopnoea index (AHI), which is the number of apnoeas plus the number of hypopnoeas per hour of sleep - (hypopnoea being reduction in airflow). An AHI of less than 10 is not likely to be associated with clinical problems. To determine whether you are suffering from sleep apnoea you must first undergo a specialist 'sleep study'. This will usually involve a night in hospital where equipment will be used to monitor the quality of your sleep. The results will enable a specialist to decide on your best course of treatment. The ultimate investigation is polysomnography, which will include:
- Electro-encephalography (EEG) - brain wave monitoring
- Electromyography (EMG) - muscle tone monitoring
- Recording thoracic-abdominal movements - chest and abdomen movements
- Recording oro-nasal airflow - mouth and nose airflow
- Pulse oximetry - heart rate and blood oxygen level monitoring
- Electrocardiography (ECG) - heart monitoring
- Sound and video recording
This is a very expensive investigation, with few centres able to offer it routinely for all suspected sleep apnoea patients. A 'mini' sleep study is more usual, consisting of pulse oximetry and nursing observation. Home sleep study is becoming more popular.
Treating Sleep Apnoea
There are several forms of treatment for sleep apnoea. In mild and moderate cases weight loss and the use of mandibular advancement devices can be wholly successful. In moderate and severe cases mandibular advancement device or nasal continuous positive airway pressure (CPAP) are normally prescribed. CPAP is the gold standard treatment for OSA.
Central & Mixed Sleep Apnoea
OSA is the commonest form of sleep apnoea, (about 4% of men and 2% of women) but there is also a condition called Central Sleep Apnoea (CSA). This is a condition when the brain does not send the right signals to tell you to breathe when you are asleep. In other words the brain 'forgets' to make you breathe. It can also be associated with weakness of the breathing muscles. The assessment for CSA is often more complicated than for OSA and the treatment has to be carefully matched to the patient's requirements. There is also a condition called Mixed Sleep Apnoea that is a combination of both obstructive and central sleep apnoea.