In people who have sleep apnea (also referred to as sleep-disordered breathing), breathing briefly stops or becomes very shallow during sleep. This change is caused by intermittent blocking of the upper airway, usually when the soft tissue in the rear of the throat collapses and partially or completely closes the airway. Each breathing stop typically lasts 10–20 seconds or more and may occur 20–30 times or more each sleeping hour.
If you have sleep apnea, not enough air can flow into your lungs through the mouth and nose during sleep, even though breathing efforts continue. When this happens, the amount of oxygen in your blood decreases. Your brain responds by awakening you enough to tighten the upper airway muscles and open your windpipe. Normal breaths then start again, often with a loud snort or choking sound. Although people who have sleep apnea typically snore loudly and frequently, not everyone who snores has sleep apnea.
Because people who have sleep apnea frequently arouse from deeper sleep stages to lighter sleep during the night, they rarely spend enough time in deep, restorative stages of sleep. They are therefore often excessively sleepy during the day. Such sleepiness is thought to lead to mood and behavior problems, including depression, and such sleepiness more than triples the risk of being in a traffic or work related accident. The many brief drops in blood-oxygen levels can be associated with morning headaches and decreased ability to concentrate, think properly, learn, and remember.
In sleep apnea, the combination of the intermittent oxygen drops and reduced sleep quality triggers the release of stress hormones. These hormones in turn raise your blood pressure and heart rate and boost the risk of heart attack, stroke, irregular heart beats, and congestive heart failure. In addition, untreated sleep apnea can lead to altered energy metabolism that increases the risk for developing obesity and diabetes. Anyone can have sleep apnea.
It is estimated that at least 12–18 million American adults have sleep apnea, making it as common as asthma. More than one-half of the people who have sleep apnea are overweight. Sleep apnea is more common in men. More than 1 in 25 middle-aged men and 1 in 50 middle-aged women have sleep apnea along with excessive daytime sleepiness. About 3 percent of children and 10 percent or more of people over age 65 have sleep apnea. This condition occurs more frequently in African Americans Asians, Native Americans, and Hispanics than in Caucasians.
More than one-half of all people who have sleep apnea are not diagnosed. People who have sleep apnea generally are not aware that their breathing stops in the night. They just notice that they don’t feel well rested when they wake up and are sleepy throughout the day. Their bed partners are likely to notice, however, that they snore loudly and frequently and that they often stop breathing briefly while sleeping. Doctors suspect sleep apnea if these symptoms are present, but the diagnosis must be confirmed with overnight sleep monitoring. This monitoring will reveal pauses in breathing, frequent sleep arousals, and intermittent drops in levels of oxygen in the blood.
Like adults who have sleep apnea, children who have this disorder usually snore loudly, snort or gasp, and have brief stops in breathing while sleeping. Small children often have enlarged tonsils and adenoids that increase their risk for sleep apnea. But doctors may not suspect sleep apnea in children because, instead of showing the typical signs of sleepiness during the day, these children often become agitated and may be considered hyperactive. The effects of sleep apnea in children may include diminished school performance and difficult, aggressive behavior. A number of factors can make a person susceptible to sleep apnea. These factors include:
- Throat muscles and tongue that relax more than normal while asleep
- Enlarged tonsils and adenoids
- Being overweight—the excess fat tissue around your neck makes it harder to keep the throat area open
- Head and neck shape that creates a somewhat smaller airway size in the mouth and throat area
- Congestion, due to allergies, that can also narrow the airway
- Family history of sleep apnea
- A medical history that includes asking you and your family questions about how you sleep and how you function during the day.
- Checking your mouth, nose, and throat for extra or large tissues—for example tonsils, uvula (the tissue that hangs from the middle of the back of the mouth), and soft palate (roof of your mouth in the back of your throat).
- An overnight recording of what happens with your breathing during sleep (polysomnogram, or PSG)
- A Multiple Sleep Latency Test (MSLT), usually done in a sleep center, is used to see how quickly you fall asleep at times when you would normally be awake. Falling asleep in only a few minutes usually means that you are very sleepy during the day. Being very sleepy during the day can be a sign of sleep apnea.