Sleep apnea affects how well you breathe at night. The cause can depend on the type of sleep apnea you’re experiencing.
Sleep apnea is a term that describes a sleep disorder where your breathing pauses and restarts while you sleep.
There are two primary types of sleep apnea: obstructive sleep apnea (OSA) and central sleep apnea (CSA). While both conditions affect your nighttime breathing pattern, their underlying causes are different.
In obstructive sleep apnea, your upper airway becomes physically blocked while you sleep, reducing or completely stopping airflow into your lungs. In central sleep apnea, dysfunction in brain signaling negatively affects how well your brain controls the muscle function necessary for proper breathing.
OSA and CSA have different underlying causes, though there can be some overlap. It’s possible to experience symptoms of OSA and CSA at the same time (known as mixed sleep apnea or complex sleep apnea syndrome).
OSA
In OSA, your upper airway becomes partially or completely blocked as your muscles relax while you sleep. This can happen for several reasons, including:
- Excess soft tissue around your airway: Fat deposits, an enlarged tongue or tonsils, and an elongated uvula (the teardrop piece of tissue that hangs at the back of the mouth) can block the airway when lying down.
- Structural differences: Some people are born with certain features, like a narrow upper airway or small lung volume, that make the airway more likely to become blocked.
- Weak airway muscles: For some people with OSA, the upper airway muscles are too weak to prevent collapse. Collagen loss due to age is one reason airway muscles might weaken.
- Reduced neural signaling: While brain signaling impairment is typically seen in CSA, it can also be a part of OSA when weak or slowed brain signals cause excessive muscle tone loss in the airway.
CSA
In CSA, improper signaling from your central nervous system (your brain and spinal cord) can result in irregular breathing during sleep. It is much more rare than OSA.
According to a 2023 review, the most common cause of this is “ventilator instability,” a state in which the brain overreacts to small changes in oxygen and carbon dioxide levels.
When carbon dioxide levels get misinterpreted as too high, hypersensitivity in the brain can trigger excessive breathing, which drops carbon dioxide levels too low and causes the brain to stop sending breathing signals altogether.
The causes of signaling issues in CSA are less clear. For some people, brain damage or neurodegenerative conditions, like dementia or Parkinson’s disease, may play a role. For others, the causes of ventilator instability are unknown.
Risk factors are circumstances that increase the likelihood you’ll experience a certain health condition. They can be genetic, biological, or related to environmental exposures.
Risk factors for OSA include:
- advanced age
- being assigned male at birth
- obesity
- large neck circumference
- certain anatomical traits like a large tongue, small airway, or low lung capacity
- family history of OSA
- living with a condition that causes fluid retention, like heart or kidney failure
- drinking alcohol
- smoking
- living with a medical condition that affects the size of your craniofacial features
- primarily sleeping on your back
- chronic nasal congestion
Risk factors for CSA include:
- experiencing brain damage
- neurodegenerative and neurologic conditions
- cardiovascular disease
- being assigned male at birth
- advanced age
- opioid use
- genetic conditions that affect muscle development and function
- premature birth
- living at a high altitude of over 2,500 meters (8,200 feet)
It’s not always possible to prevent sleep apnea. Some risk factors, like genetics, age, and underlying medical conditions, cannot be changed.
However, in some cases, the risk can be lowered by following certain
- quitting smoking, if you do smoke
- limiting or avoiding alcohol consumption, if you do drink
- sleeping on your side
- getting enough sleep each night
- managing any health conditions you have
Not all sleep apnea can be traced to a preventable or unpreventable cause. When the cause of sleep apnea can’t be determined, it’s known as idiopathic sleep apnea.
Despite their differing causes, OSA and CSA are treated similarly.
First-line sleep apnea treatments focus on keeping your airway open while you sleep and working on long-term goals related to weight management, lifestyle modifications, and management of underlying diseases contributing to sleep apnea.
To keep your airway open while you sleep, doctors prescribe a type of positive airway pressure (PAP) therapy, such as:
- continuous positive airway pressure (CPAP)
- bi-level positive airway pressure (BiPAP)
- auto-titrating positive airway pressure (APAP)
PAP therapies deliver a constant flow of air into your airway through a mask worn while you sleep. This steady stream of air keeps your airway open. PAP may be used alongside medications like bronchodilators that reduce inflammation in your airways.
Doctors might also consider custom-made oral devices to correctly position your mouth, tongue, and jaw during sleep or surgery to remove excess tissue or address anatomical issues.
In
Sleep apnea results in your breathing stopping and starting again while you sleep. The cause can depend on the type of sleep apnea you’re experiencing. There are two primary types of sleep apnea: obstructive sleep apnea (OSA) and central sleep apnea (CSA).
If you’ve been diagnosed with OSA, your airway becomes physically blocked at night, restricting or preventing airflow. If you’ve been diagnosed with CSA, unusual brain signaling causes interruptions in your normal breathing pattern at night.
You can’t always prevent sleep apnea, but managing underlying medical conditions and improving certain lifestyle habits can help reduce your risk factors.
