Before looking more closely at what sleep apnea is, here are a few key questions to ask yourself:
- Have you or your partner noticed that you sometimes stop breathing while sleeping?
- Do you sometimes wake up in the night feeling breathless, perhaps choking or gasping for air?
- Are you a loud snorer, sometimes with long pauses between snores?
- Do you feel sleepy during the day, even if you slept a lot?
- Do you have insomnia, and maybe also feel sleepy during the day?
If you answered yes to any of these questions, there’s a possibility – though by no means certain – that you might have a sleep disorder called sleep apnea.
People with sleep apnea struggle for air and stop breathing while sleeping. The interruptions occur several times per hour (over 30 in severe cases) and can last for many seconds, even minutes, at a time.
Sleep apnea can have serious consequences for your health if left untreated. So if you do answer yes to any of the questions above, it’s important to speak to your doctor about it.
Unlike some sleep disorders, which can be dealt with by self-help and good sleep habits alone, sleep apnea requires professional help.
And in this article you’ll find an overview of the two main types of sleep apnea, looking at the symptoms, risk factors, diagnosis and treatment options. I’ll also point out some of the main similarities and differences between the two types.
The 2 main types of sleep apnea
There are two main types of sleep apnea. Both are categorized as sleep-related breathing disorders in the latest version of the International Classification of Sleep Disorders (3rd edition).
Obstructive sleep apnea (OSA)
Obstructive sleep apnea is the most common type, and is associated with a blockage of the person’s airways.
It’s traditionally estimated to affect 3-7% of people worldwide, though a recent study suggests that 10-17% of the US population could be afflicted, though many would be unaware of it. There are also distinct adult and child forms of OSA.
Central sleep apnea (CSA)
Central sleep apnea is less common, and is linked with a lack of physical effort from the body’s respiratory system. This then results in a reduction or stoppage of air flow.
The exact prevalence is unknown as it’s suspected that many people remain undiagnosed. The number who have it also differs according to the sub-type, as well as the particular group of people. For example, a higher percentage of elderly people would have it than younger people.
There are in fact eight sub-types of CSA that vary based on age of onset, cause and other features. Furthermore, some people may have a mix of the two main types of sleep apnea.
Symptoms of sleep apnea
There are a few symptoms which are associated with both forms of apnea. Not all sufferers will experience all of these symptoms though.
- Loud snoring.
- The person repeatedly stops breathing while sleeping due to obstructed airways and/or central respiratory weakness. This is sometimes seen by another person.
- Sudden awakening, possibly with breathlessness.
- Sufferers may report excessive sleepiness during waking hours because the interruptions make it harder to achieve deep sleep.
- Insomnia might also be a result, either alone or as well as daytime sleepiness.
- Difficulty with attention during the day.
There are also symptoms linked with just one type of apnea:
- While anyone can snore, people with OSA often do so more frequently and loudly. It also tends to be more abrupt or startling, especially when returning to sleep from a breathing interruption. They may also wake up holding their breath, gasping or choking.
- CSA is identifiable by reduced chest/abdominal movements when breathing. This symptom is very subtle in most cases though, making it difficult to detect by sight or experience alone.
Possible obstructive sleep apnea risk factors
Ideally, you can try to avoid developing OSA by maintaining good overall health, especially if any of the suggested risk factors below apply to you:
- Obesity: extreme overweightness that’s defined by a body-mass index (BMI) at least 20% higher than recommended.
- Large tonsils.
- Having a large neck even when maintaining a healthy weight.
- Males face a greater risk.
- People with Down syndrome are at higher risk.
- Being older than 40.
- A family history of sleep apnea.
- Recessed (tucked-in) chin, often visible as an overbite.
- Children with neuromuscular diseases, cerebral palsy, gastroesophageal reﬂux or sickle cell disease.
- Exposure to tobacco smoke.
Possible central sleep apnea risk factors
- People who wake frequently in the night, either because they are susceptible to waking up easily, or because they have sleep maintenance insomnia.
- People whose breathing is affected more than usually by Carbon Dioxide.
- Opioid use.
- The presence of medical conditions like heart disorders, brain tumor or stroke.
- Some OSA treatments, like the use of a forced-air device, can increase the risk of CSA.
- Males are at a higher risk.
- People over 65 are at higher risk of developing other CSA risk factors.
- Traveling to a higher altitude than accustomed may disrupt breathing because of decreased oxygen availability.
If you meet the criteria for one or more of the risk factors for either type of apnea, it’s a good idea to watch for symptoms so that they can be addressed while the problem is relatively new.
Apneas aren’t deadly on their own, but they are associated with an increased risk of life-threatening conditions that will be discussed below. Accordingly, symptoms of sleep apnea must be taken seriously and a medical professional should be consulted as soon as possible if they appear.
What causes sleep apnea?
Each type of sleep apnea can be caused by a wide range of issues. The following examples are by no means exhaustive.
Causes of obstructive sleep apnea (OSA)
- Deviated septum (displaced nasal tissue) blocking the airway.
- Overly relaxed throat muscles block the airway.
- Airway blocked by tongue.
- Airway blocked by fatty tissue.
- Naturally narrow airways.
Causes of central sleep apnea (CSA)
- Disruption of the brain area related to breathing by stroke, tumor or other health issue.
- Severe obesity can depress the respiratory system.
- Use of narcotics depresses the respiratory system.
- One of many medical conditions.
- Unaccustomed high altitude exposure disrupts breathing due to lower oxygen levels.
How is sleep apnea diagnosed?
The presence of sleep apnea in any form is best confirmed by a test conducted in a sleep lab. A patient would spend one or more nights sleeping at the lab while their breathing and other body activities are monitored.
To diagnose sleep apnea, at least one of the symptoms listed above needs to be found. Additionally, a Polysomnography sleep test needs to show specific results regarding the actually breathing abnormalities.
A polysomnography test measures a large number of things, such as:
- Electrical brain activity.
- Sleep stage progression.
- Eye movements.
- Heart beats.
- Body movements.
- Blood oxygen levels.
- Breathing patterns.
As you can imagine, there are several instruments that must be worn during sleep in order for these measurements to be taken including, but not restricted to:
- Wires attached to the body with pads to measure electrical activity.
- A variety of stretchable bands secured around the chest and abdominal areas to record breathing movements.
- Finger clips to monitor blood flow properties (heart rate, oxygen saturation, pressure).
Several other tests may also be needed if central sleep apnea is suspected. Magnetic resonance imaging (MRI) could be used to look for physical obstructions in the neck and/or chest area. Additional lung and heart tests may also be required.
While sleep lab visits are the preferable setting for diagnosis, there are also portable kits that can be taken home by patients with suspected OSA if necessary.
Portable devices measure breathing through short tubes that are placed in the nose and mouth. They may also have the necessary belts and clips for testing chest/abdominal mechanics and blood flow.
Results are recorded within the machine so that they can later be retrieved by a doctor for assessment.
CSA diagnosis always requires in-person monitoring by professionals, so tests must be completed in a lab if the central type of apnea is suspected.
And before coming to a diagnosis, a doctor would also need to rule out other possible explanations, such as another sleep or medical disorder, medication or substance use.
Treatments for OSA
The most common treatment for OSA is the use of a CPAP machine. CPAP stands for “continuous positive airway pressure”.
These devices include a main base, an attached hose and a face mask that secures to your head with straps.
When used during sleep, the CPAP will force a mild but steady stream of air into the nasal passages to help keep the airways from collapsing.
A prescription is needed to obtain a CPAP machine and it has to be calibrated for each individual’s needs, so a couple of visits to a medical facility may be necessary.
There are also a number of lifestyle changes that are recommended for people with mild to moderate cases of OSA:
- Weight loss.
- Avoiding alcohol and other sedatives that may relax muscles.
- Sleeping on your side.
- Quitting smoking.
- Regular exercise.
Dental appliances can be used in less severe cases to move the tongue or other tissues out of the way and/or to align the jaw for better air passage. These devices require fitting by an experienced dentist and come in a wide variety of models, though they may cause jaw pain or chewing problems.
Surgery could be necessary to treat some forms of OSA. For example, if tonsils are blocking the airway then a tonsillectomy could be employed to remove them. Surgery is usually avoided if possible though, due to the risk of infection and serious respiratory complications.
Treatments for CSA
Individual cases of CSA must be carefully diagnosed and targeted for treatment of the underlying cause. A CPAP or similar (but stronger) device may be used to assist in the meantime.
Oxygen therapy is necessary in more severe cases. If medication is found to be the cause, then it will need to be changed or have its dosage reduced.
Living with sleep apnea
The most important points in managing sleep apnea are sticking to your treatment plan and making the appropriate lifestyle changes. If sleep apnea isn’t addressed properly, it can lead to many serious conditions, such as:
- High blood pressure.
- Increased risk of heart disease, heart attack or stroke.
- Type 2 diabetes.
- Irregular heart beat.
- Worsening memory and concentration.
- Car accidents.
Obtaining a proper diagnosis and adhering to the recommended treatment is important, and may help reduce the likelihood of these potentially fatal developments.
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