Individuals with low muscle tone and soft tissue around the airway (e.g., due to obesity), and structural features that give rise to a narrowed airway are at high risk for sleep apnea. The elderly are more likely to have Sleep Apnea than young people.
Men are more typical sleep apnea sufferers than women and children, although it is not uncommon in the latter two. Men are more likely to have it than women before age 50. After age 50, the risk is the same for men and women.
Among obese patients, 70% have Sleep Apnea which worsens in severity and prevalence with increasing obesity. Among cardiac patients, 30–50% have it, and among patients with strokes, 60% have sleep apnea.
Common symptoms include loud snoring, restless sleep, and sleepiness during the daytime. Diagnostic tests include home oximetry or polysomnography in a sleep clinic.
As already mentioned, snoring is almost a uniform finding in an individual with this syndrome, but many people snore without having apnea. Snoring is the turbulent sound of air moving through the back of the mouth, nose and throat.
The loudness of the snoring is not indicative of the severity of obstruction, however, if the upper airways are tremendously obstructed, there may not be enough air movement to make much sound. Even the loudest snoring does not mean that an individual has sleep apnea syndrome.
The sign that is most suggestive of sleep apnea occurs if snoring stops. If it does, along with breath, while the persons' chest and body tries to breathe - that is literally a description of an event in the sleep apnea syndrome. When breathing starts again, there is typically a deep gasp, and then the resumption of snoring.
When high blood pressure is caused by Sleep Apnea, it is distinctive in that, unlike most cases of high blood pressure (so-called essential hypertension), the readings do not drop significantly when the individual is sleeping. Stroke is associated with sleep apnea. Sleep apnea sufferers also have a 30% higher risk of heart attack or premature death than those unaffected.
In the June 27, 2008 edition of the journal Neuroscience Letters, researchers revealed that people with Sleep Apnea show tissue loss in brain regions that help store memory, thus linking Sleep Apnea with memory loss. Using magnetic resonance imaging (MRI), the scientists discovered that Sleep Apnea patients' mammillary bodies were nearly 20 percent smaller, particularly on the left side. One of the key investigators hypothesized that repeated drops in oxygen lead to the brain injury.