What is Obstructive Sleep Apnea?
Obstructive sleep apnea (sometimes spelled “apnoea”) is a common sleep-related breathing disorder involving breathing interruptions during sleep. These brief interruptions, or apneas, usually last a few seconds and can occur as frequently as 20 to 30 times per hour. They can include choking, gasping, or loud snoring.
Although the person experiencing OSA often isn’t aware of the condition, OSA decreases levels of oxygen in the blood and increases levels of carbon dioxide in the body. Untreated OSA increases the risk of cardiovascular disease, cancer, stroke, diabetes, dental decay, obesity and death.
In obstructive sleep apnea, airway obstruction causes breathing difficulties during sleep. This differs from central sleep apnea, another sleep-related breathing disorder, in which breathing difficulties stem from faulty brain signaling rather than an airway obstruction.
Symptoms of Obstructive Sleep Apnea
As a sleep-related breathing disorder, OSA shares symptoms with other disorders in this category, like central sleep apnea and complex sleep apnea. Complex sleep apnea is a combination of central and obstructive sleep apnea—breathing interruptions result from both airway obstruction and neuromuscular problems.
Sleep apnea can cause sleep-related laryngospasm, in which the sleeper wakes up suddenly with a feeling of suffocation. Any attempts to speak come out as a wheeze. People who have these spasms often have gastroesophageal reflux, which could indicate a link between these conditions.
Other symptoms of obstructive sleep apnea include:
Symptoms of sleep-related breathing disorders like OSA worsen during the winter. This may be due to allergies and seasonal weight gain (many people get heavier in the winter). Weather conditions such as high atmospheric pressure (more common in winter), high humidity (more common in summer) and carbon monoxide (more common in urban areas) can worsen sleep apnea symptoms. Cold and flu season peaks during the winter months, so seasonal increases in respiratory infections and irritation may trigger OSA symptoms.
Who has obstructive sleep apnea? Research suggests that around 40 million Americans experience obstructive sleep apnea. Men are more susceptible to sleep apnea than women. Nearly 20 percent of men and nine percent of women experience sleep apena at some point in their lives. Moderate-to-severe apnea affects nine percent of males and four percent of females. Two percent of children are also affected by sleep apnea, mostly infants under one year of age.
Experts attribute increasing rates of sleep apnea to improved diagnostics and increasing obesity rates. In the early 90s, approximately 3 percent of the general population had sleep apnea.
Sleep apnea is most prevalent in middle-aged males. Males are between two and three times as likely to develop apnea than women. Males typically have a larger neck circumference and a longer pharyngeal airway, which make them more susceptible to sleep apnea.
The incidence of obstructive sleep apnea increases with age and peaks between ages 40 and 60. After age 60, sleep apnea rates begin to decrease.
Pregnant women have higher rates of sleep apnea. Nearly 80 percent of pregnant women experience symptoms of sleep apnea at some point in their pregnancy, usually in the third trimester. This seems to be due to a combination if enlarged blood vessels, hormonal changes, and weight gain.
Smokers are three times as likely to develop apnea as nonsmokers, because smoking causes increased upper airway inflammation and fluid retention. The increased risk is reversible; once a smoker quits, their sleep apnea risk decreases.
What causes Obstructive Sleep Apnea?
Obstructive sleep apnea is usually caused by carrying excess weight. Excess body weight expands soft tissues in the throat and mouth, which relax during sleep and obstruct the airway. Because OSA is linked to obesity, conditions that increase the risk of obesity, like metabolic syndrome and diabetes, are associated with an increased risk for OSA. People with cleft lips and cleft palates may have higher rates of sleep-related breathing disorders, including OSA.
Research suggests that people taking opioid medication may have higher rates of sleep apnea. This may occur because opioid pain relievers relax soft tissues surrounding the throat.
In some cases, OSA exists without obesity or another related health condition. There may be a genetic component to OSA risk.
Sleep apnea is highly underdiagnosed. According to the National Institutes of Health, only 25 percent of adults with sleep apnea symptoms sought medical attention. Indeed, one of the goals of the government’s Healthy People 2020 initiative is to raise this percentage. People experiencing symptoms of obstructive sleep apnea like excessive daytime tiredness, frequent night arousals accompanied by a choking or gasping, or unexplained weight gain should talk to a doctor about sleep apnea.
Obstructive sleep apnea is diagnosed with polysomnography, or an overnight sleep study. During a polysomnogram, a technician measures heart, lung and brain activity. A polysomnogram can detect apneas, or breathing interruptions during sleep, to diagnose obstructive sleep apnea.
Because sleep apnea can decrease levels of oxygen in the blood, a small device called an oximeter may be used to measure blood oxygen saturation. If the blood is saturated with oxygen (carrying as much as it can), the saturation level is 100%. A level below 90% is a sign of hypoxemia, or low blood oxygen, which can result from sleep apnea. A level between 80% and 90% is a sign of mild apnea and a level below 80% is severe.
The Apnea-Hyponea Index was created to quantify the severity of apnea. Under 5 stoppages is considered normal (no apnea). Mild apnea is 5 to 15 incidences per hour, 15-30 is considered moderate, and 30 or more severe.
The most common treatment for obstructive sleep apnea is continuous positive airway pressure, known as CPAP. In CPAP therapy, a bedside machine generates a continuous flow of positive air pressure. The machine connects to a mask worn on the face overnight. The machine supplies positive airway pressure that keeps the airway open during sleep, reducing or eliminating apneas (breathing interruptions) during sleep.
An alternative to CPAP is BPAP, bilevel positive airway pressure, which provides two levels of that sits next to the bed and has a mask connected to it that the person wears while sleeping. It forces pressure into the nose and mouth so the airway does not collapse and the person sleeps without choking or gasping awakenings.
Some people request sleep apnea treatment without the mask required by CPAP. In some cases, sleep apnea can be treated with a dental device. These devices, fitted by a specially trained dentist, help hold the soft tissues of the mouth and throat in place during sleep. They are smaller and more portable than CPAP machines, but may not help alleviate OSA symptoms in all patients.
One of the most effective sleep apnea treatments is weight loss. Along with dramatically reducing the risk of OSA, weight loss also reduces the risk of related health conditions like diabetes, cardiovascular disease, and metabolic syndrome. Weight loss is free of side effects and allows patients to sleep without a CPAP machine or dental device.
Surgical treatment for OSA may include uvulopalatopharyngoplasty (also called UPPP or UP3) surgery to remove soft tissue in the throat and widen the airway. back. Removing the tonsils or adenoids also can relieve apnea, especially in children.
Your physician may recommend weight loss, avoidance of alcohol/sedatives, or sleeping in a position other than the back.
Drugs cannot correct sleep-related breathing disorders but may treat the underlying causes of sleep apnea, including narrowed or restricted airways. Domperidone (normally used to suppress vomiting and nausea) and decongestants pseudoephedrine or phenylephrine may help open airways to reduce sleep apnea symptoms.
There is some evidence that the antidepressant medication mirtazapine (Remeron) helps improve sleep apnea symptoms. This is the most effective drug for apnea found so far, but the evidence is based only on a small trial. Mirtazapine is not used widely in apnea treatment.
The drug acetazolamide is used to treat altitude sickness, and research suggests it might benefit people with sleep apnea. The drug, sold under the brand name Diamox, helps increase oxygen levels in the bloodstream. When people ascend to alpine levels, they sometimes have trouble getting enough oxygen. Sleep apnea produces some of the same effects, and Swiss scientists found acetazolamide may help, although this is not yet an accepted treatment.
Research shows that melatonin may have beneficial effects for people with sleep apnea. Melatonin can help induce sleep and regulate sleep patterns. Per research, it may also help reduce oxidative stress in the body caused by sleep apnea.