What is Sleep Apnea?

Understanding the causes of the most popular sleep disorder in America.

By Alesandra Woolley

Mar 19th, 2021

Expert Insights from Dr. Luis Javier Peña-Hernández, MD, FCCP, a lung health specialist at PCSI, the largest integrated pulmonary and chest specialty group in Palm Beach County and Dr. Jennifer Le, Diplomate of Dental Sleep Medicine (ABDSM) and practitioner of Wake Dental Sleep in Raleigh, NC.

Sleep apnea is a potentially life-threatening sleep disorder characterized by abnormal pauses (apneas) in breathing during sleep. It was once known as Pickwickian syndrome after the symptoms of a character described in Charles Dickens’ 1836 book Pickwick Papers

According to the American Sleep Apnea Association, it is estimated that 22 million Americans suffer from obstructive sleep apnea. At least 4% of men and 2% of women are affected. However, it’s common for sleep apnea to go undiagnosed because most people who have it aren’t aware of their disorder.

Despite the popularity of this disease, most people don’t take the risks associated with sleep apnea serious, and the risks are huge. Research indicates individuals with this sleep disorder have an increased mortality rate due to a higher risk of a stroke or heart attack.

Mattress Advisor set out to understand the causes sleep of apnea, what happens if it goes untreated, and how you can determine if you or a loved one has this disorder. To help answer our questions, we called on the expertise of Dr. Luis Javier Peña-Hernández, MD, FCCP, a lung health specialist at PCSI, the largest integrated pulmonary and chest specialty group in Palm Beach County and Dr. Jennifer Le, Diplomate of Dental Sleep Medicine (ABDSM) and practitioner of Wake Dental Sleep in Raleigh, NC.

Types of Sleep Apnea

“There are several types of sleep apnea. These include central sleep apnea, obstructive sleep apnea, and mixed sleep apnea–a combination of the two,” says Dr. Luis Javier Peña-Hernández.

  • Central sleep apnea – a relatively uncommon form which occurs when the brain fails to send the signal to the muscles to take a breath; this results in periods where there is no muscular effort to breathe
  • Obstructive sleep apnea (OSA) – a much more common form, where the brain sends signals to the muscles and the muscles do make an effort to take a breath, but they are unable to comply effectively because an obstructed airway prevents an adequate flow of air
  • Mixed sleep apnea, a mixture of the two, is also possible but extremely uncommon.

Sleep hypopnea is similar in many respects to sleep apnea, with similar symptoms and long-term effects, although it is less common. It is caused by excessively shallow breathing or an abnormally low respiratory rate, rather than by complete breathing pauses due to obstructions or other causes. This typically leads to loud, heavy snoring, interrupted several times an hour by choking sounds or snorts followed by a silence of up to 20 seconds as insufficient air flows into the lungs. 

Sleep hypopnea and the various kinds of sleep apnea mentioned above are often lumped together under the heading “sleep-disordered breathing.” Upper airway resistance syndrome is a similar, but milder, form of sleep-disordered breathing.

Patients who suffer from sleep apnea are constantly jerked out of reparative sleep. Not only is sleep disrupted, but so is oxygen flow. Sometimes oxygen flow can be interrupted greater than 10 times in one hour — which is enough for your body to enter crisis mode. Because of the complete loss of muscle tone associated with REM sleep, that is the most common time to experience apneas, and they are relatively rare during non-REM sleep.

What Causes Sleep Apnea?

“Sleep apnea can be caused by obesity, inflammation, or an abnormality in the anatomy of the jaw, soft palate, airway, or tonsils,” says Dr. Peña-Hernández.

We’ll explore each of these causes:


First and foremost, sleep apnea can be caused by an anatomic issue. Some of these include jaw position, the structure of the soft palate, excessive tissue narrowing the airway, or enlarged tonsils. Anatomic issues can sometimes be genetic.


Another more common cause is being overweight or obese. “When someone is overweight, the extra weight carried in the neck can compress and obstruct the airway,” Dr. Le explains.


Finally, sleep apnea can be caused by inflammation of the soft palate from being sick or eating inflammatory foods.

Symptoms of Sleep Apnea

Dr. Le shared with us the most common symptoms of sleep apnea. These include:

  • Loud snoring
  • Restless sleep
  • Periods of not breathing during sleep
  • Irritability or personality change
  • Difficulty concentrating and poor memory
  • Drowsy driving

What is Obstructive Sleep Apnea?

Obstructive sleep apnea is a serious disorder in which breathing pauses repeatedly for 10 seconds or longer during sleep. In the most common case of obstructive sleep apnea, breathing is disrupted by a physical block to the airflow caused by a collapse of the soft tissues in the throat and respiratory tract (the same tissues as produce the sound of snoring, which almost always accompanies sleep apnea). 

“When left untreated and undiagnosed, sleep apnea can be a very dangerous sleep disorder,” says Dr. Peña-Hernández.

During these pauses in breathing (or apneas), the sleeper effectively starts to suffocate (in addition to experiencing a sharp loss in blood oxygen levels and increased carbon dioxide levels), and the brain sends an immediate emergency signal to the body to wake up. When the sleeper wakes and takes a deep breath, the brain is replenished and the person is able to go back to sleep.

Snoring: It’s More Serious Than You Think

Snoring is known to be something that people poke fun at. “Our society has made snoring something to chuckle about, but it’s not normal,” Dr. Le explains.

What people fail to realize is that snoring is actually a sleep disorder in itself.

“Snoring occurs when there is a partial obstruction to the flow of air through the nose and mouth. The sound occurs when loose structures in the throat, like the uvula and soft palate, vibrate as air passes over them. Snoring can get worse when the muscles in the back of the throat are too relaxed either from drugs that induce sleep or alcohol consumption.”

Snoring is an interruption of you and your partner’s quality of sleep. When sleep is interrupted, you can’t complete your sleep stages, which has various repercussions that we’ll discuss later on.

Snoring is the precursor to sleep apnea and has similar causes. Dr. Le recommends that if you snore every night, you should go to your primary physician and have an open conversation about it. That way, you can work together to rule out other disorders.

Long-term Implications if Sleep Apnea Goes Untreated

Sleep apnea that goes untreated has a number of consequences. The frequent partial awakenings that are caused by sleep apnea (often referred to as micro-awakenings) lead, over time, to chronic sleep deprivation and excessive daytime sleepiness. Sleep apnea can disturb sleep to such an extent that, even after a full night in bed, the sleeper does not feel rested due to the compromised quality of the sleep.

In addition to excessive daytime sleepiness, the constant sleep interruptions may lead to loss of energy, headaches, forgetfulness, and, in the longer term, to high blood pressure, heart attack, stroke, depression, or other mood disorders. The lowered blood oxygen level during sleep apnea can also disrupt the stages of sleep in a person’s sleep cycles.

Let’s take a deeper look at the impacts of sleep apnea if left untreated.

Interrupted Sleep That Leads to Forgetfulness

Did you know people who suffer from sleep apnea can’t dream? That’s because restorative sleep is interrupted so frequently, they can’t make it far enough into their sleep cycle where dreaming occurs.

Dr. Le explains that the body uses sleeping hours to repair itself and process what it learned that day. The brain’s ability to compartmentalize information during sleep assists in memory recall. That’s why patients who suffer from sleep apnea have difficulty concentrating or remembering information.

Hormone Disruption

Additionally, lack of sleep causes all sorts of hormones to be out of whack — including cortisol, insulin, leptin and, ghrelin to name a few.

  • Cortisol: At night, cortisol levels should decrease. However, if you have lost sleep, these levels may stay elevated. This promotes insulin resistance, which is a risk factor for obesity and diabetes.
  • Leptin: This hormone signals satiety to the brain, meaning it suppresses appetite. Lack of sleep causes a decrease in leptin. In other words, your brain is telling you that you’re still hungry, even when you’re full.
  • Ghrelin: Related to leptin, ghrelin stimulates appetite. It’s been proven lack of sleep increases levels of ghrelin. Meaning, if you aren’t getting enough sleep, you might be taking in more calories than you need, especially carbohydrates.

Learn more about how sleep affects hormones here.

The ramifications of poor sleep are cyclical. Take an overweight individual that suffers from sleep apnea for example. This individual may have sleep apnea due to excess weight that obstructs the airway. Because of their sleep apnea, they suffer from sleep deprivation. Sleep deprivation throws their levels of leptin and ghrelin out of whack, which increases their appetite. The excess calories from unnecessary snacking cause them to put on more weight that may worsen their sleep apnea.

Additional Health Risks

There are many other health risks associated with sleep apnea other than the consequences that come with lack of restful sleep. Risk of stroke, heart failure, diabetes, depression, high blood pressure, and mental impairment are far more common in people with sleep apnea. Wondering why? Dr. Le explained it like this:

“If the main highway in your city is shut down that creates detours. Meaning traffic is going to be redirected to roads that were never built to accommodate the amount of traffic a highway can accommodate. As a result, these roads start to break down from potholes, pavement deterioration, etc. A similar thing happens if your main airway is obstructed. The body overcompensates for the problem by compromising other systems: blood vessels, organs, etc.”

Comorbid Conditions

A comorbid condition can be the direct result of a primary condition, in this case sleep apnea, or it may be that the comorbid condition plays a role in creating the primary condition. We have a bit of a which came first question here, but in either case, it is almost always the comorbid condition that causes the more serious threat to life. Just how serious? Let’s take a look.

Type II Diabetes

Both sleep apnea and type II diabetes are associated with weight gain and obesity, and it may be that extra weight causes and aggravates both of these conditions. Type II diabetes is linked to sleep apnea and about 80% of people who have type II diabetes, also have sleep apnea. They damage that diabetes does to your body can be fatal, and it is strongly correlated with heart attack and stroke.


Extra weight is a primary factor in developing sleep apnea and obesity is common among people who have sleep apnea. Since sleep apnea causes an interruption to sleep, which further disrupts hormones that can cause weight gain, we see a vicious circle of weight gain which causes sleep apnea, which causes a lack of sleep, which leads to weight gain—round and round it goes. Sleep apnea is further associated with metabolic syndrome, making hard to lose weight. Obesity puts an enormous strain on the heart and is associated with fatal episodes.

Cardiovascular Disease

38,000 people die from heart disease yearly where sleep apnea is a complicating factor. 60% of people with heart failure have sleep apnea. Having sleep apnea increases the risk of a heart attack by 30%. Having sleep apnea increases the risk of stroke by between 30 and 50%. These are very real statistics on the likelihood of acquiring cardiovascular disease comorbid with sleep apnea.


Sleep apnea doesn’t cause cancer that we know of, but if you have cancer and sleep apnea together, it increases the risk of death from cancer. The sleep apnea, which decreases health in many ways, seems to be a tipping factor in whether you are more likely to recover from cancer or to have it be fatal.

There is no doubt that the conditions associated with sleep apnea raise your risk for serious problems and can be a direct cause of death.

Who is at Risk for Sleep Apnea?

Men are more likely to suffer from sleep apnea than women and children, and the risk increases with age, body weight and smoking habits. In particular, sleep apnea is highly correlated with obesity, mainly due to excess fat on the sides of the neck that can cause obstructions in the airway. Several other conditions also increase the risk of sleep apnea, including menopause, asthma, epilepsy, Down syndrome, etc. In children, it may result from enlarged tonsils or adenoids.

Often, a sufferer from sleep apnea is completely unaware of the condition, which may therefore continue for years without identification. Even then it may only be identified by someone else witnessing the episodes or complaining about the loud snoring that usually accompanies it, or merely as a consequence of the ongoing daytime sleepiness, fatigue and irritability that result from it.

It has become apparent in recent years that those with sleep apnea are more vulnerable to a variety of parasomnias, such as sleep-walking, sleep-sex, sleep-eating, confusional arousals, night terrors, etc, as well as other sleep disorders like periodic limb movement disorder, restless legs syndrome, etc.

Treatment Options

The goal of any type of sleep apnea treatment is to keep the airway open. With that being said, patients need to know they have options.

Related: Sleep apnea testing

One of the most important things Dr. Le stressed to us about treatment options for sleep apnea is that they should be modified to best suit a patient’s needs. For this to happen, patients must see a trained doctor that addresses the issue from a holistic point of view. That includes managing your sleep hygiene*, monitoring weight gain and finding the mode of sleep apnea treatment that works best for you.

Common treatments include lifestyle changes (such as avoiding alcohol and other muscle relaxants, losing weight and quitting smoking), sleeping on a 30 degree angle or on one’s side or using a weight blanket of various weight , various kinds of oral/dental appliances or masks (particularly continuous positive airway pressure, or CPAP, masks, which remains the leading therapy for severe sleep apnea), or even surgical procedures to increase the size of the airway.

*By managing sleep hygiene we mean monitoring your sleep habits. Dr. Le suggests limiting the amount of TV you watch at night, reducing the amount of alcohol consumed before bed and finding the proper mattress to name a few. Basically, create an environment that is conducive to getting the best sleep possible.

Read More: Best Mattress for Sleep Apnea

Here are some potential treatment options that may be available to you:

CPAP Therapy

Continuous Positive Airway Pressure (CPAP) is considered the standard of care for sleep apnea. However, forced oxygen is of no use if you don’t wear the CPAP.

Oral Appliance Therapy

An alternative to CPAP therapy, for those who do not wear or cannot wear CPAP, is oral appliance therapy. There are a variety of oral appliances available. The choice of which is best for you is based on many factors, including the severity of the sleep apnea, jaw structure and personal preference. Visit Dr. Le’s website to learn more about oral appliance therapy.

Other Tips for Relieving Sleep Apnea Symptoms

On top of oral appliance therapy, here are a few tips Dr. Le recommends to help relieve the symptoms of sleep apnea:

  • Try avoiding alcohol and sedatives before you go to bed. These substances can make symptoms worse because they can cause relaxation of the airway.
  • Try not to sleep on your back. Sleeping on your back can cause your tongue and soft palate to collapse to the back wall of your throat which obstructs the airway and promotes snoring.
  • Weight loss reduces the amount of weight that compresses the airway; thus, decreasing the number of times breathing stops.

“The sooner you identify sleep apnea the better,” Dr. Le tells us. If sleep apnea runs in the family, keep an awareness that your likelihood to develop it increases.

If you have experienced any of the symptoms listed above and believe you may have sleep apnea, Dr. Le recommends seeing your physician to discuss your sleep health. You may also use an app to record your snoring to help identify whether you have reason for concern. Check out this  list of apps that record snoring published by the American Sleep Association to start.

Dr. Le leaves us with this: “Remember that sleep management is a team effort. If your sleeping partner suffers from snoring or sleep apnea, that affects your quality of sleep too.” Don’t be afraid to start a conversation with your bed partner about how your sleeping affects them too. Work together to get the help you need.

Expert Bios

Dr. Luis Javier Peña-Hernández, MD, FCCP, is a lung health specialist at PCSI, the largest integrated pulmonary and chest specialty group in Palm Beach County. His areas of expertise include asthma and immunotherapy, COPD, lung cancer, and invasive diagnostic techniques in pulmonary medicine including endo-bronchial ultrasound and diagnostic bronchoscopy. He is also one of the few experts in cardiopulmonary exercise testing and exercise physiology in Palm Beach County.

Dr. Jennifer LeDMD, D- ABDSM, CPCC, ACC received her dental degree from the University of Pittsburgh in 2001. She now practices at Wake Dental Sleep in Raleigh, NC. Dr. Le is the Director of the American Board of Dental Sleep Medicine (ABDSM), an independent board of examiners that was established in 2004 for duly licensed dentists who treat sleep-related breathing disorders with oral appliance therapy, an effective alternative treatment to commonly used CPAP machines. Additionally, Dr. Le is Chair of Accreditation for the American Academy of Dental Sleep Medicine (AADSM). We chose to speak to Dr. Le for this campaign given her prestige in the field of Dental Sleep Medicine.