Central vs Obstructive Sleep Apnea: The Primary Differences
If you find yourself consistently exhausted and drowsy during the day, it is possible you may have sleep apnea. This is quite a common sleep disorder, one which in the US alone affects around 30 million people.
With sleep apnea, there are frequent pauses to your breathing when you sleep – prompting your body to awake for air. These incidents can be very brief, and you’re likely unaware they occur.
Very often, sleep apnea goes undiagnosed. However, the impact on your sleep cycle leads to excessive daytime fatigue and serious health problems like heart disease, high blood pressure, as well as depression.
There are different types of sleep apnea. The two main types are obstructive sleep apnea (OSA) and central sleep apnea (CSA).
Obstructive Sleep Apnea (OSA)
OSA results from a physical obstruction of the upper airways and is the most common form of sleep apnea. When sleeping, the throat muscles can relax and collapse to the extent they partially or fully block the airways, disrupting the flow of oxygen to the lungs.
You may awake gasping for air as the brain reacts to the drop in blood oxygen levels.
The blocked airways often lead to snoring, one of the prime symptoms of OSA. However, you can still have sleep apnea and not snore. Sleep deprivation and drops in blood oxygen levels can increase the risk of serious health issues such as heart disease, stroke and diabetes.
A major risk factor for OSA is being overweight, increasing the amount of throat muscle tissue which can block the airways overnight. Other risk factors for OSA include:
- large neck size
- large tongue or tonsils
- a recessed chin
- smoking and alcohol
- being over 40 years old
- family history and genetics
Central Sleep Apnea (CSA)
Around 20% of sleep apnea cases can be attributed to CSA. With CSA the breathing pauses result from a faulty brain signal that affects breath—so it is therefore a neurological disorder.
Someone with CSA can physically breathe, but the brain is not sending the correct messages to breathe – so nighttime breathing is seriously impeded.
Many of the symptoms of CSA such as breathing pauses, fatigue, snoring and waking with a dry mouth are similar to those for OSA. However, CSA is often associated with other underlying health conditions including Parkinson’s disease, obesity, heart disease and stroke.
Certain medications, including opioids and benzodiazepines may also play a role in developing CSA. Further risk factors for CSA include residing at high altitude and excessive alcohol consumption.
Sleep Apnea Treatment
If you display symptoms of sleep apnea it is important to consult with your doctor. Some symptoms such as frequent brief awakenings and snoring may only be noticed by a sleep partner.
Your doctor can arrange an in-home test or a sleep study that usually involves an overnight stay at a sleep clinic. Once sleep apnea has been diagnosed there are treatments to reduce the symptoms – which also reduces risk of serious medical complications.
The leading treatment for OSA is continuous positive airway pressure (CPAP) therapy. The CPAP device delivers pressurized air through a tube to a mask worn overnight.
The mask may be a full-face mask or one which covers just the nose. The pressurized air prevents the collapse of the airways, allowing for a free flow of oxygen to the lungs.
BiPAP is another non-invasive treatment for OSA, which can be an option if someone is struggling to adapt to CPAP. While both treatments work to keep the airways clear by delivering pressurized air, BiPAP has two pressure settings, with the setting lower when you exhale compared to when you inhale. Struggling to exhale against the fixed pressure setting of CPAP can be a common issue.
For mild to moderate OSA, an oral device (similar to a dental retainer) does the same job without the need for CPAP. The device helps keep the airways open by moving the lower jaw and tongue forward when you are sleeping.
As one of the primary risk factors for OSA is obesity, weight loss through lifestyle changes can also help reduce OSA symptoms. Lifestyle changes include:
- Regular exercise
- Nutritious diet
- Less alcohol
- Quit smoking
Sleep position: Gravity pulls down the throat tissues that block the airways, so changing your sleeping position may also be considered. If you tend to sleep on your back, you may be advised to sleep on your side, with your doctor able to suggest methods to help you make this change.
Surgery is usually considered the final option in treating OSA. Surgery would be used to remove tonsils and any throat muscle tissue that is causing the airways to become blocked when sleeping. Surgery could also be used to adjust the jaw in order to open the airways.
CPAP can also be an option in treating CSA. However, as this form of sleep apnea is often associated with serious underlying health conditions, addressing these conditions may improve your CSA symptoms.
Treatments for heart disease, diabetes and high blood pressure may be indicated.
An advanced form of CPAP called Adaptive Servo-Ventilation (ASV) may prove the best option for those with CSA.
With ASV, your breathing is monitored, and the pressure of the air delivered adjusted to suit your breathing patterns through the night. These subtle changes to the pressure levels of the air you inhale can make ASV more comfortable for some people compared to CPAP which delivers the same level of pressure.
The key is diagnosis. By understanding which form of sleep apnea you have, your doctor can work with you to form the most suitable treatment plan to reduce your symptoms and return you to uninterrupted nights of sleep. Sleep apnea increases the risk of serious health problems and if you show any symptoms you should consult with your doctor.