For a diagnosis of sleep apnea, more than five episodes per hour must occur.In central sleep apnea (CSA), the basic neurological controls for breathing rate malfunction and fail to give the signal to inhale, causing the individual to miss one or more cycles of breathing. If the pause in breathing is long enough, the percentage of oxygen in the circulation will drop to a lower than normal level (hypoxaemia) and the concentration of carbon dioxide will build to a higher than normal level (hypercapnia). In turn, these conditions of hypoxia and hypercapnia will trigger additional effects on the body. Brain cells need constant oxygen to live, and if the level of blood oxygen goes low enough for long enough, brain damage and even death will occur. A systemic disorder, sleep apnea is associated with a wide array of effects, including increased risk of car accidents, hypertension, cardiovascular disease, myocardial infarction, stroke, atrial fibrillation, insulin resistance, higher incidence of cancer, and neurodegeneration. The exact effects of the condition will depend on how severe the apnea is and on the individual characteristics of the person having the apnea. Treatment may include lifestyle changes, mouthpieces, breathing devices, and surgery. Effective lifestyle changes may include avoiding alcohol, losing weight, stopping smoking, and sleeping on ones side. Breathing devices include the use of a CPAP machine. With proper use, CPAP improves outcomes. Evidence suggests that CPAP may improve sensitivity to insulin, blood pressure, and sleepiness.
Snoring is the turbulent sound of air moving through the back of the mouth, nose, and throat. Although not everyone who snores is experiencing difficulty breathing, snoring in combination with other risk factors has been found to be highly predictive of OSA. 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 apneas occurs when snoring stops. Up to 78% of genes associated with habitual snoring also increase the risk for OSA.Other indicators include (but are not limited to): hypersomnolence, obesity (BMI ≥ 30), large neck circumference—16 in (410 mm) in women, 17 in (430 mm) in men — enlarged tonsils and large tongue volume, micrognathia, morning headaches, irritability/mood-swings/depression, learning and/or memory difficulties, and sexual dysfunction. The term "sleep-disordered breathing" is commonly used in the U.S. to describe the full range of breathing problems during sleep in which not enough air reaches the lungs (hypopnea and apnea). Sleep-disordered breathing is associated with an increased risk of cardiovascular disease, stroke, high blood pressure, arrhythmias, diabetes, and sleep deprived driving accidents. When high blood pressure is caused by OSA, 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.