What is Sleep Apnea?
As is true with any medical condition, the question “what is sleep apnea” can have a short answer or a long answer.
In Short? Start with the Basics
According to the dictionary, “apnea” means “a transient cessation of respiration.” Putting the term together, “sleep apnea” means temporarily stopping breathing while sleeping. While that may sound benign, sleep apnea is a sleep disorder principally affecting breathing, and sleep-disordered breathing can be a serious illness – both medically and economically speaking.
People with sleep apnea don’t pause their breath once or twice a night for a second or two. Patients suffering from severe sleep apnea often stop breathing – as in, no air at all moving in or out of the lungs – for several seconds, even up to a minute or more – hundreds of times during the night. A second definition for apnea is a word you might be familiar with: asphyxia, or “death by” fame.
There are three different types of sleep apnea: obstructive sleep apnea (the most common), central sleep apnea, and mixed or complex sleep apnea. The good news is that modern sleep medicine specialists can diagnose sleep apnea by means of a sleep study and treat it very effectively. The bad news is that people with untreated sleep apnea can experience blood oxygen levels that are severely out of whack, leading to adverse health consequences that can be grave and often permanent. Sleep apnea has been associated with diabetes, stroke, high blood pressure, and heart failure, as well as a myriad of stress-related illnesses.
Even for the short answer, it’s important to realize that sleep apnea is pretty common, affecting some 22 million people in the United States, and that it can be dangerous. Perhaps the most commonly identified risk factor is obesity. And the scariest part? Many people who have it don’t know that they have it.
Most people with sleep apnea exhibit several signs and symptoms including loud snoring, excessive daytime sleepiness, and difficulty concentrating. For more sleep apnea signs and symptoms, click here.
The American Sleep Apnea Association is one of several organizations devoted exclusively to supporting sleep apnea patients. However, virtually any group concerned with other sleep disorders (such as the National Sleep Foundation, which you can find here) will devote a significant portion of its resources to sleep apnea information.
That’s the short answer. For a deeper dive into this most distressing of sleep disorders, keep reading.
The Long Answer – Deep Dive into Sleep and Disordered Sleep Breathing
Sleep. It’s critical to good health. And while some people need more or less than others, everyone needs to sleep. When we don’t get a good night’s sleep, very bad things can happen.
While no one understands precisely what happens when we do it, we know that sleep is crucial to physical and emotional health. When permitted to run their natural course, sleep’s rhythms and cycles steer a sleeper through all of the stages necessary for sleep to have its healing, regenerative effect. A person who sleeps soundly and for as long as he or she needs to is able to reap a multitude of health benefits.
Sound sleep is restorative; it helps us recover from the daily toll of life. And, while you might think that any sleep is sound sleep and therefore good for you, such is not the case.
A person afflicted with untreated sleep apnea doesn’t experience restorative sleep. In fact, when they sleep, they stop breathing multiple times an hour, all night long. When you stop breathing while sleeping, bad things happen. The result is much as if you did not sleep at all.
Sleep deprivation can have profound and dangerous consequences for almost every aspect of your life – mental fogginess, fatigue, slowed reflexes, compromised immune system, increased stress, decreased coping skills, depression, heart disease, stroke, diabetes, etc.
The Medical Specialty Concerned with Sleep Apnea
Sleep medicine is a recognized, multidisciplinary clinical practice. The types of physicians who provide medical advice in connection with sleep disorders primarily include internal medicine specialists, pulmonologists (lung specialists), neurologists (specialists in neurological disorders), and psychiatrists. Sleep medicine further implicates a wide swath of additional medical specialties ranging from otolaryngologists (ear, nose, and throat) to cardiologists (heart) to maxillofacial (jaw and sinuses) surgeons. When sleep apnea is the subject of inquiry, that swath gets even broader, encompassing endocrinologists because of sleep apnea’s association with type 2 diabetes and other hormonal disorders.
Types of Sleep Apnea
Sleep apnea is all about breathing or, rather, not breathing while one is asleep. Practitioners usually classify it into one of three types:
- Obstructive sleep apnea
- Central sleep apnea
- Complex or Mixed sleep apnea
Complex or mixed sleep apnea is a combination of obstructive sleep apnea and central sleep apnea. Many doctors take the position that “complex sleep apnea” should not be recognized as a separate category, since it is merely a combination of the other two. The American Sleep Apnea Association, on the other hand, insists that complex sleep apnea be given its own status as a distinct type of sleep apnea. Regardless, any type of untreated sleep apnea can result in serious health problems.
Obstructive sleep apnea occurs when there is a mechanical blockage of the upper airway. Usually, this happens when the soft tissue at the back of the throat and the muscles relax. The soft palate and other tissues collapse after you fall asleep. Loud snoring – often cited as a symptom of sleep apnea – is the result. However, not everyone who snores loudly suffers from sleep apnea, and not all who suffer from sleep apnea snore loudly.
Central sleep apnea occurs when there is no blockage of the upper airway but, for some reason, the respiratory control center in the brain doesn’t send the appropriate signals to the correct muscles in the body to cause breathing to occur.
Irrespective of the cause and no matter which of the types of sleep apnea is involved, the effect is the same: failure to get a full night’s sleep. Despite being in bed for the requisite time, the patient does not get the restorative sleep they need to maintain good health. From dry mouth to high blood pressure to workplace accidents to behavioral disorders, the consequences of both obstructive sleep apnea and central sleep apnea can be grave.
Who Suffers from Sleep Apnea?
Almost anyone can have sleep apnea, but men are at increased risk, and your chance of having sleep apnea increases with age. Obstructive sleep apnea affects about 25% of men and 10% of women, at least pre-menopausal women, and those who are overweight overwhelmingly more than those who are not. (Central sleep apnea is far less common.) Once women enter menopause, their weight-gain patterns change, and the number of women afflicted with sleep apnea approaches parity with men.
As far as risk factors go, obesity and obstructive sleep apnea are closely related. Only three percent of people within recommended weight ranges suffer from sleep apnea, while twenty percent of those classified as obese are troubled with obstructive sleep apnea. It’s important to realize, however, that obstructive sleep apnea is not just a problem for the overweight.
Another of the breathing problems correlated with obstructive sleep apnea is nasal congestion, which almost inevitably results in a dry mouth and scratchy soft palate. A family history of sleep apnea also plays a role in one’s susceptibility to sleep apnea.
Type 2 Diabetes, Obesity, and Sleep Apnea – A Special Relationship
As mentioned, type 2 diabetes is notably related to sleep apnea, as it is with obesity. Given that losing weight reduces the likelihood of contracting both diabetes and sleep apnea, one might think that the causal link is with obesity rather than sleep apnea. Studies have shown, however, that there is an independent connection between increased blood sugar levels and sleep apnea, thus identifying diabetes as one of the more salient risk factors of sleep apnea.
The correlation between sleep apnea and diabetes undoubtedly is strong, but it also is insidious. It has been estimated that up to 83% of people with type 2 diabetes have sleep apnea, yet may not know it.
The connection between obesity and sleep apnea may be mechanical, especially when the excess weight gain is in the neck, tongue, and upper belly. When relaxation occurs in the upper airway, increased mass in these areas leads directly to enhanced pressure in the back of the throat and on breathing structures, thereby closing the airway – a classic example of obstructive sleep apnea syndrome.
While some consider obesity to be one of the symptoms of sleep apnea, the association likely is reversed. That is, weight loss is one method for treating or alleviating sleep apnea.
Symptoms of Sleep Apnea and Diagnostic Criteria
Symptoms of sleep apnea include extreme daytime sleepiness (falling asleep while driving or at a stoplight, for instance, which leads to motor vehicle crashes), loud snoring, reports of gagging or gasping during sleep, consistently waking up with a dry mouth or sore throat, high blood pressure that is difficult to control even with blood pressure medication, insomnia (difficulty staying asleep, as opposed to falling asleep), relatives with a history of sleep apnea, type 2 diabetes, and metabolic syndrome.
Definitive diagnosis of sleep apnea requires scientific observation of the patient during an overnight sleep study. Typically, this is accomplished by conducting a sleep study at a sleep center or sleep laboratory. The patient goes to a sleep laboratory, is connected to a monitor, and spends one or more nights there, sleeping normally. Throughout the night, as the patient snores loudly, the equipment in the sleep laboratory analyzes the patient’s breathing patterns and measures the number of apnea episodes that occur, i.e., how many times and how often the patient stops breathing during the night.
Physicians typically grade the seriousness of obstructive sleep apnea on a scale ranging from mild to severe, based upon the apnea-hypopnea index, or AHI. The AHI measures the frequency per hour of pauses in breathing that the patient experiences while sleeping. For instance, an AHI of 25 means that the patient stops breathing 25 times an hour during the night.
- Mild obstructive sleep apnea – an AHI between 5 and 15
- Moderate obstructive sleep apnea – an AHI between 15 and 30
- Severe obstructive sleep apnea – an AHI greater than 30
Whether you need treatment for sleep apnea depends upon its severity and is a decision that you should make in conjunction with your sleep specialist. Sometimes, your doctor will recommend treatment even if your sleep disorder is not symptomatically acute or your AHI is not especially high. For instance, risk factors for heart disease or diabetes might prompt a recommendation for sleep apnea treatment, even in the face of a lower AHI.
Effective Treatment is Available
The good news is that effective treatment for sleep apnea is available. Continuous positive airway pressure (or CPAP) is highly effective at alleviating sleep apnea and ameliorating its effects. You can find a full discussion of CPAP technology and methodology elsewhere on this site.
Studies emphasize not only the effectiveness but the importance of using a CPAP machine to manage sleep apnea. Real-time increases in free fatty acids, glucose, and cortisol (a damaging stress hormone) have been verified in sleep apnea patients not using their machines, while documented decreases occur during use.
Although there is speculation that failure to use his CPAP machine may have contributed to former U.S. Supreme Court Justice Antonin Scalia’s death, possibly from atrial fibrillation, illustrating the short-term or acute importance of treatment for sleep apnea, it’s the long-term effects that are the most critical. The buildup of toxic substances in the bloodstream resulting from sleep-disordered breathing over long periods increases the likelihood of developing intractable diabetes and leads to harmful systemic effects such as vascular stiffness and high blood pressure, contributory to cardiac disease and heart failure.
Both the American Sleep Apnea Association and the National Sleep Foundation provide information on surgical procedures available to modify the nose, tongue, soft palate, or other structures in the upper airway, as well as bones in the lower jaw or neck. Generally, however, surgery is not considered as a first-line option, particularly given the success of continuous positive airway pressure options. Various appliances – sometimes called “mandibular advancement devices” – are available that mechanically adjust soft tissue and the jaw to decrease obstruction in the patient’s upper airway can also be fitted by medical professionals. For patients suffering from symptomatic heart failure from central sleep apnea, a device similar to a pacemaker can be implanted to sense when a patient hasn’t taken a breath in too long a time and stimulate the phrenic nerve.
Simply put: Sleep apnea is no joke. It is more common than you think, and it’s a dangerous condition that requires medical treatment. The longer you go without addressing it, the greater the harm will be.