Sleep apnea is a breathing disorder that occurs during sleep. Sleep apnea is not a single disease entity, but rather include several disorders. Apnea is Greek for "without breath."
Sleep apnea occurs in two types:
More than half of all cases of sleep apnea are diagnosed in people 40 years of age or older. The condition also is more common in men than women and is a major contributor to daytime drowsiness. Thirty percent to 60 percent of people with severe daytime sleepiness have sleep apnea.
Signs and symptoms
The signs and symptoms of obstructive and central sleep apnea overlap, sometimes making the type of sleep apnea more difficult to determine. The most common signs and symptoms of obstructive and central sleep apnea include:
Disruptive snoring may be a more prominent characteristic of obstructive sleep apnea, while awakening with shortness of breath may be more common with central sleep apnea.
Obstructive sleep apnea occurs when the muscles in the back of your throat relax. These muscles support the soft palate, uvula, tonsils and tongue.
When the muscles relax, your airway is narrowed or closed as you breathe in, and breathing is momentarily cut off. This lowers the level of oxygen in your blood. Your brain senses this decrease and briefly rouses you from sleep so that you can reopen your airway. This awakening is usually so brief that you don't remember it.
You can awaken with a transient shortness of breath that corrects itself quickly with one or two deep breaths. You may make a snorting, choking or gasping sound. This pattern can repeat itself 20 to 30 times or more each hour, all night long. Your ability to reach the desired deep, restful phases of sleep is impaired, and you'll probably feel sleepy during your waking hours.
People with obstructive sleep apnea may not be aware that their sleep was interrupted. In fact, many people with this type of sleep apnea think they sleep well all night.
Central sleep apnea, which is far less common, occurs when your brain fails to transmit signals to the breathing muscles. You usually awake abruptly due to the progressive rise in the level of carbon dioxide in your blood and the accompanying drop in your level of oxygen. You may awaken with shortness of breath. People with central sleep apnea may be more likely to remember awakening than people with obstructive sleep apnea are.
Sleep apnea may occur if you're young or old, male or female. Even children can have sleep apnea, a problem more common than it's known. But certain factors put you more at risk:
Obstructive sleep apnea
Central sleep apnea
In both obstructive and central sleep apnea, congestive heart failure is a significant risk factor. High blood pressure is common in both types of sleep apnea. Sudden drops in blood oxygen levels that occur during sleep apnea increase blood pressure and strain the cardiovascular system, raising the risk of heart failure and stroke. If there is underlying heart disease, these repeated multiple episodes of low blood oxygen (hypoxia or hypoxemia) can lead to sudden death from a cardiac event.