Sleep apnea is a common condition characterized by breathing problems such as loud snoring, pauses in breathing, and gasping for air during sleep.
There are three types of sleep apnea, and while the symptoms are largely the same, the
mechanism (or cause) is somewhat different among each type.
Here’s a look at the three types of sleep apnea and how they differ.
People who have sleep apnea experience intermittent episodes of pauses in breathing; the term “apnea” comes from the Greek word for “breathless.”
Such moments of apnea occur repeatedly during sleep in people with the condition, causing individuals to partially wake up multiple times during the night as they struggle to breathe. Someone with severe sleep apnea may have these partial arousals from sleep 240 times per night or more during eight hours of sleep.
Because these awakenings are typically very brief, the person with sleep apnea may not even be aware that they are experiencing interrupted sleep.
But the episodes can wreak havoc on the sleep cycle and prevent the person with sleep apnea from getting enough restful, healthy sleep, which can lead to exhaustion, sleepiness, and other symptoms and complications.
The most common type of sleep apnea is obstructive sleep apnea, sometimes referred to as OSA. With OSA, the throat muscles in the back of your throat — which naturally become more relaxed during sleep — collapse too much and block the flow of normal air into the lungs, which prevents normal breathing.
Why It Happens
The muscles in the back of the throat support the back of the roof of the mouth (the soft palate), the triangular piece of tissue hanging from the soft palate (the uvula), the tonsils, the side walls of the throat, and the tongue. When these muscles collapse too much, those tissues can fall back into the throat, partially or completely blocking the normal flow of air in your airway. When the airway is blocked you may start to snore, which is why this symptom is common in OSA. (Not everyone who snores has sleep apnea.)
When your brain senses that you aren’t getting enough oxygen, it signals your body to wake up enough so that you can reopen your airway, and you may gasp for air. Simply put, having obstructive sleep apnea means that not enough air can get into the lungs at night, and your brain wakes you up to breathe, says Robson Capasso, MD, chief of sleep surgery and a professor of otolaryngology and head and neck surgery at Stanford University School of Medicine in California.
Risk Factors for Obstructive Sleep Apnea
Obstructive sleep apnea tends to be most common in people who are heavier, have larger necks, and are older and male, among other risk factors, including various health conditions.
Research indicates that cases of obstructive sleep apnea have risen significantly in the last two decades. This is likely due to two main factors: Obesity (one of the most common risk factors for OSA) has increased dramatically; and there is more awareness about sleep apnea among doctors and the public at large, so more people are being screened and diagnosed, says James Rowley, MD, a pulmonologist and program director of the Sleep Medicine Fellowship at Rush University Medical Center in Chicago.
Diagnosis and Treatment
Obstructive sleep apnea can be treated with a device to keep your airway open, such as a machine that pushes air pressure into your lungs through a mask that fits over your nose and mouth while you sleep, called continuous positive airway pressure (CPAP).
Other OSA treatment options include other breathing machines, mouthpieces designed to keep your jaw forward and keep your airway open, or surgery (in more severe cases) to remove tonsils or other tissue that could cause airway obstruction or move your jaw to open up your airway.
The U.S. Food and Drug Administration (FDA) also recently approved Zepbound (tirzepatide) as the first prescription medication specifically for adults with moderate-to-severe obstructive sleep apnea (OSA) and obesity.
Your doctor may also advise you to lose weight and to avoid sleeping on your back, to prevent gravity from further pushing your tongue, tonsils, and other soft tissues in your throat into your airway.
Another type of sleep apnea — central sleep apnea — is less common than obstructive sleep apnea. It can also be trickier to diagnose and treat.
Why It Happens
Unlike obstructive sleep apnea, which is caused by a mechanical problem that blocks the airway, central sleep apnea occurs because the brain is not sending the proper messages to the muscles that control breathing. (“Central” refers to the central nervous system.)
Risk Factors
While central and obstructive sleep apneas share many symptoms — such as episodes of pauses in breathing, constant awakenings during the night, and extreme sleepiness during the day — central sleep apnea often affects people who have underlying illnesses such as a brain infection; stroke, or other conditions that affect the brainstem; and
heart failure.
Certain drugs, such as opioids or benzodiazepines, can also play a role in central sleep apnea. “In patients who use opioids on a chronic basis, the breathing mechanisms can get numbed,” Dr. Capasso explains.
Diagnosis and Treatment
Your doctor may refer you to a sleep specialist for a diagnosis if they suspect central sleep apnea, which may involve an overnight sleep test to rule out obstructive sleep apnea or other
sleep disorders.
The sleep specialist may also work with your cardiologist or order scans of your head and heart to rule out other contributing illnesses.
Treatment of central sleep apnea typically means addressing the medical problems that are causing the apnea in the first place — for instance, treating heart problems may improve central sleep apnea symptoms. Changing medications can sometimes be beneficial, and positive pressure ventilation can be helpful, too, using either CPAP or another type of ventilator, called bilevel positive airway pressure (BiPAP).
Like CPAP, BiPAP delivers pressurized air to your lungs, but a BiPAP delivers a higher amount of air pressure when you breathe in than when you breathe out compared with CPAP, which delivers the same amount of pressure as you breathe in and out.
Another ventilator sometimes recommended for central sleep apnea is an adaptive servo-ventilation (ASV) machine. It works similarly to CPAP and BiPAP, but ASV is more specialized in that it measures your breathing patterns and customizes the air pressure to keep your breathing stable throughout the night. However, ASV is not suitable for those with moderate to severe heart failure, so it’s important to talk to your doctor about your medical history before using ASV.
Doctors have more recently identified a third type of sleep apnea called complex sleep apnea, also known as treatment-emergent central sleep apnea, which is a combination of obstructive sleep apnea and central sleep apnea.
Patients with this type of sleep apnea may at first seem to have obstructive sleep apnea, but unlike typical patients with obstructive sleep apnea, these patients’ symptoms are not fully addressed with the use of CPAP. (Since CPAP is usually quite effective in treating obstructive sleep apnea, its failure to alleviate symptoms would suggest the patient had central sleep apnea.)
In patients with complex sleep apnea syndrome, breathing problems persist even after the airway obstruction is addressed and treated, which means something besides the collapsing throat muscles are also contributing to the apnea.
In some patients, complex sleep apnea resolves with continued use of their CPAP device. Others may be treated with a different kind of positive airway pressure therapy.
The problem is that there is still a lot of debate among sleep medicine specialists about what exactly is going on in complex sleep apnea, or what the key characteristics that define it are.
Emily Davis
James Bennett
David Thompson
Susan Bennett
Chloe Jenkins
Marcus Vance