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(A-Z listing includes diseases, conditions, tests and procedures)

Sleep Apnea: Diagnosis, Treatment and Research


As many as 20 million people in the United States have sleep apnea, which means the body does not breathe properly during sleep, resulting in involuntary breathing pauses. Each time breathing is interrupted, reflexes eventually trigger the brain to open the upper airway. When breathing resumes, the person may gasp, snore or snort.

People who have sleep apnea may experience excessive daytime sleepiness. They may also awaken with a headache, sore throat or dry mouth. Because obstructive sleep apnea is often most pronounced during REM sleep (when the body’s muscles naturally relax), people who suffer from it may notice issues related to memory, learning consolidation and even sexual function—all of which are strongly influenced by REM sleep.

“However, it is also important to realize that some people who are later diagnosed with horrific sleep apnea may not have any significant daytime or nighttime symptoms,” says Johns Hopkins sleep expert Jonathan Jun, M.D. Often, these patients visit the sleep clinic after their bed partner expresses concern after witnessing them snoring or stopping breathing at night. For this reason, listening to a bed partner’s observations can be an important way to diagnose sleep apnea that would otherwise go unnoticed by the sleeper.

Without treatment, sleep apnea can deprive your body of deep sleep, blocking its restorative properties. “Sleep apnea is a dangerous condition that leads to reductions in the amount of oxygen in your blood and brain during the night,” says Johns Hopkins sleep expert Jason P. Kirkness, Ph.D. “This puts an extra load on your heart, blood vessels, brain and metabolism, which can lead to negative consequences such as a stroke, cardiovascular disease and type 2 diabetes, as well as a decreased quality of life due to excessive sleepiness during the day.”

Risk Factors

“One of the greatest risk factors for sleep apnea is obesity,” says Kirkness. Men also have a higher prevalence of sleep apnea than women, and the risk increases with age for both men and women. Here is some insight into these and other risk factors associated with sleep apnea.

Age. Sleep apnea is more common in people older than age 40, though it can occur at any age. As we grow older, the overall strength of skeletal muscles decreases, which may make older adults more vulnerable to sleep apnea.

Gender. Sleep apnea is more common in men than women, however women are often underdiagnosed. A woman’s risk increases after menopause, which may indicate that hormones play a role.

Ethnicity. People who are Latino or African American are at a greater risk of sleep apnea.

Genetics. Sleep apnea tends to run in families, so experts believe there may be a genetic component to it. Some genetic disorders such as Down syndrome can increase a person’s risk of sleep apnea, often because of anatomical differences in the mouth and upper airway.

Anatomical differences. An enlarged tongue, recessed jaw, narrow airway, enlarged tonsils or uvula, or other anatomical factors may predispose a person to sleep apnea. Among children, the top cause of sleep apnea is enlarged tonsils.

Pregnancy. Physical changes due to pregnancy can also be a trigger.

Drugs, smoking and alcohol. These substances can affect the upper airway by dulling protective reflexes or causing inflammation.

Diagnosis & Treatment


The only way to officially diagnose sleep apnea is with an overnight sleep study (polysomnogram), says Jun. These studies usually take place in a sleep laboratory, where a computer monitors the patient’s brain waves, eye movement, muscle activity, heart rate and breathing during sleep. Home testing is possible, but it may be less effective at picking up milder cases. “Most insurance companies will cover a polysomnogram when there is accurate documentation supporting the need for it,” says Jun.

Sleep apnea is diagnosed based upon the patient’s apnea-hypopnea index (AHI), or the average number of apneic events recorded per hour of sleep. An AHI of 5 results in a diagnosis of sleep apnea, though there are various levels of severity:

  • Mild: 5 to 15 episodes

  • Moderate: 15 to 30 episodes

  • Severe: More than 30 episodes


With proper treatment, sleep apnea symptoms can usually be completely controlled or eliminated. Current options include:

  • Continuous positive airway pressure (CPAP) machine: This is the gold standard for the treatment of sleep apnea. CPAP works by pushing air into the nose or mouth, which prevents the upper airway from collapsing during sleep. If a CPAP machine is needed, the patient will return to the sleep clinic for a CPAP titration study, during which adjustments are made to customize the CPAP settings for that patient. People who have trouble tolerating CPAP should discuss their concerns with their health care provider, says Jun. Modifications to the settings or a different type of mask may be all that’s needed to remedy the problem. 

  • Mandibular advancement device (MAD): These dental devices are worn at night to move the jaw into a position that will open the airway, generally by lifting the tongue off the back of the throat.

  • Surgery: Surgeons may make modifications to open the airway by removing large tonsils or reducing the size of the tongue or uvula. If obesity is a contributing factor, bariatric or weight-loss surgery may be helpful.

Living With … 

These lifestyle and behavioral changes may also help reduce the symptoms of sleep apnea.

Quit smoking. Smoking causes inflammation that narrows the airway. Kicking the habit may help minimize sleep apnea symptoms.

Modify usage of alcohol and medications. Alcohol and certain medications (such as opiates, sedatives and muscle relaxants) can increase relaxation of the muscles in and around the upper airway. Avoid alcohol after dinner, avoid combining alcohol and sedative medications, and talk to your doctor about whether your medications may be worsening your sleep apnea.

Achieve a healthy weight. For most people, weight loss of 10 percent can reduce the number of apneic events.

Sleep on your side. For some people with sleep apnea, lying on their back can worsen sleep apnea symptoms due to the effects of gravity. There are pillows and devices that can help you stay on your side during sleep, which may minimize symptoms. Some people sew a tennis ball into the back of a T-shirt to prevent them from rolling onto their back.

Communicate with your surgeon. People who have sleep apnea are at a greater risk of certain complications during and after surgery. Because anesthesia affects breathing, people with sleep apnea may need special monitoring during and after surgery. They may also experience extended recovery times afterward. If you have sleep apnea, it’s important to share that information with all of your health care providers.

Related Conditions

Sleep apnea has been linked to an increased risk of stroke, hypertension, irregular heartbeat, heart attack, type 2 diabetes, death from any cause, cancer and accidents on the road and at work due to daytime drowsiness. “Generally, the higher the number of sleep interruptions per night, the greater your risk of these problems. However, we are still learning what factors cause some people to be especially vulnerable,” says Jun.

With these conditions, it is difficult to say which comes first, adds Kirkness. Sleep apnea may raise the risk of these conditions, but the opposite may also be true. For example, someone who is experiencing sleep apnea have a greater risk of a stroke due to the increased load on the brain and heart caused by repeated oxygen deprivation at night. On the other hand, a person who has a stroke that affects the muscles involving the airway may develop sleep apnea.


Johns Hopkins researchers are looking at novel therapies to treat sleep apnea. They are also further studying its causes and effects in the body. Among their recent studies:

  • An electrical implant may stimulate airway muscles. Johns Hopkins researchers are testing the effectiveness of a relatively new treatment that involves implanting a device into muscles around the tongue. The patient activates the device prior to sleep, and it signals the nerves to tense the tongue so that it will not retract during sleep.

  • A new therapy could offer a CPAP alternative. Kirkness and other Johns Hopkins researchers are studying the use of nasal high-flow therapy (nasal insufflation). This therapy uses narrow tubing (like that used by people who need to be on oxygen) to deliver pressurized, warmed, humidified air and/or oxygen through the nose. In people who snore or have mild sleep apnea, this may be sufficient to open the airway. Although it may not be as effective as CPAP for the majority of patients with sleep apnea, it may be a viable option for people with mild sleep apnea who have problems tolerating the use of a CPAP device.

  • The risks of sleep apnea to metabolic and cardiovascular health. Johns Hopkins researchers are examining the effects of sleep apnea on other organ systems during sleep to learn which features of sleep apnea, and which patients, have the greatest need for treatment.

#TomorrowsDiscoveries: Neurons That Control Biological Rhythms and Sleep - Dr. Seth Blackshaw

The hypothalamus is a cherry-sized part of the brain that serves as the master regulator of many behaviors, including biological rhythms, sleeping and eating.

Dr. Seth Blackshaw's lab has identified genes that control the formation of neurons in the hypothalamus that control biological rhythms and sleep, paving the way for therapies for sleep disorders, obesity and diabetes.

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