sleep apnea sleep apnea sleep apnea, also spelled sleep apnoea, is a sleep disorder in which pauses in breathing or periods of shallow breathing during sleep occur more often than normal. each pause can last for a few seconds to a few minutes and they happen many times a night. in the most common form, this follows loud snoring. there may be a choking or snorting sound as breathing resumes. because the disorder disrupts normal sleep, those affected may experience sleepiness or feel tired during the day. in children, it may cause hyperactivity or problems in school. sleep breathing disorderother namessleep apnoea, sleep apnea syndromeobstructive sleep apneapronunciation/æpˈniːə/, /ˈæpniə/ specialtyotorhinolaryngology, sleep medicinesymptomspauses breathing or periods of shallow breathing during sleep, snoring, tired during the daycomplicationsheart attack, cardiac arrest, stroke, diabetes, heart failure, irregular heartbeat, obesity, motor vehicle collisions, alzheimer's disease, and premature deathusual onsetvaries; 50% of women age 20–70typesobstructive sleep apnea (osa), central sleep apnea (csa), mixed sleep apnearisk factorsoverweight, family history, allergies, enlarged tonsils, asthmadiagnostic methodovernight sleep studytreatmentlifestyle changes, mouthpieces, breathing devices, surgeryfrequency~ 1 in every 10 people, 2:1 ratio of men to women, aging and obesity higher risk sleep apnea may be either obstructive sleep apnea (osa), in which breathing is interrupted by a blockage of air flow, central sleep apnea (csa), in which regular unconscious breath simply stops, or a combination of the two. osa is the most common form. osa has four key contributors; these include a narrow, crowded, or collapsible upper airway, an ineffective pharyngeal dilator muscle function during sleep, airway narrowing during sleep and unstable control of breathing (high loop gain). it is often a chronic condition. other risk factors include being overweight, a family history of the condition, allergies, and enlarged tonsils. some people with sleep apnea are unaware they have the condition. in many cases it is first observed by a family member. sleep apnea is often diagnosed with an overnight sleep study. 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 one's 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. long term compliance, however, is an issue with more than half of people not appropriately using the device. in 2017, only 15% of potential patients in developed countries used cpap machines, while in developing countries well under 1% of potential patients used cpap. without treatment, sleep apnea may increase the risk of heart attack, stroke, diabetes, heart failure, irregular heartbeat, obesity, and motor vehicle collisions. alzheimer's disease and severe obstructive sleep apnea are connected because there is an increase in the protein beta-amyloid as well as white-matter damage. these are the main indicators of alzheimer's, which in this case comes from the lack of proper rest or poorer sleep efficiency resulting in neurodegeneration. having sleep apnea in mid-life brings a higher likelihood of developing alzheimer's in older age, and if one has alzheimer's then one is also more likely to have sleep apnea. this is demonstrated by cases of sleep apnea even being misdiagnosed as dementia. with the use of treatment through cpap, there is a reversible risk factor in terms of the amyloid proteins. this usually restores brain structure and diminishes cognitive impairment. osa is a common sleep disorder. a large analysis in 2019 of the estimated prevalence of osa found that osa affects 936 million—1 billion people between the ages of 30–69 globally, or roughly every 1 in 10 people, and up to 30% of the elderly. sleep apnea is somewhat more common in men than women, roughly a 2:1 ratio of men to women, and in general more people are likely to have it with older age and obesity. signs and symptoms people with sleep apnea have problems with excessive daytime sleepiness (eds) and impaired alertness. osa may increase risk for driving accidents and work-related accidents. if osa is not treated, people are at increased risk of other health problems, such as diabetes. due to the disruption in daytime cognitive state, behavioral effects may be present. these can include moodiness, belligerence, as well as a decrease in attentiveness and energy. these effects may become intractable, leading to depression. there is evidence that the risk of diabetes among those with moderate or severe sleep apnea is higher. finally, because there are many factors that could lead to some of the effects previously listed, some people are not aware that they have sleep apnea and are either misdiagnosed or ignore the symptoms altogether. risk factors sleep apnea can affect people regardless of sex, race, or age. however, risk factors include: being male obesity age over 40 large neck circumference (greater than 16–17 inches) enlarged tonsils or tongue narrow upper jaw nasal congestion allergies receding chin gastroesophageal reflux a family history of sleep apnea smoking alcohol, sedatives and tranquilizers may also promote sleep apnea by relaxing throat muscles. people who smoke tobacco have sleep apnea at three times the rate of people who have never done so. central sleep apnea is more often associated with any of the following risk factors: being male an age above 65 having heart disorders such as atrial fibrillation or atrial septal defects such as pfo stroke high blood pressure is very common in people with sleep apnea. mechanism when breathing is paused, carbon dioxide builds up in the bloodstream. chemoreceptors in the bloodstream note the high carbon dioxide levels. the brain is signaled to awaken the person, which clears the airway and allows breathing to resume. breathing normally will restore oxygen levels and the person will fall asleep again. this carbon dioxide build-up may be due to the decrease of output of the brainstem regulating the chest wall or pharyngeal muscles, which causes the pharynx to collapse. people with sleep apnea experience reduced or no slow-wave sleep and spend less time in rem sleep. complications osa is a serious medical condition. daytime fatigue and sleepiness, cardiovascular problems and eye problems are considered potential complications of osa. osa may also be a risk factor of covid-19. people with osa have a higher risk of developing severe complications of covid-19. diagnosis despite this medical consensus, the variety of apneic events (e.g., hypopnea vs apnea, central vs obstructive), the variability of patients' physiologies, and the inherent shortcomings and variability of equipment and methods, this field is subject to debate. within this context, the definition of an event depends on several factors (e.g., patient's age) and account for this variability through a multi-criteria decision rule described in several, sometimes conflicting, guidelines. oximetry oximetry, which may be performed over one or several nights in a person's home, is a simpler, but less reliable alternative to a polysomnography. the test is recommended only when requested by a physician and should not be used to test those without symptoms. home oximetry may be effective in guiding prescription for automatically self-adjusting continuous positive airway pressure. classification there are three types of sleep apnea. osa accounts for 84%, csa for 0.9%, and 15% of cases are mixed. obstructive sleep apnea main article: obstructive sleep apnea screenshot of a psg system showing an obstructive apnea. no airway obstruction during sleep. airway obstruction during sleep. obstructive sleep apnea (osa) is the most common category of sleep-disordered breathing. the muscle tone of the body ordinarily relaxes during sleep, and at the level of the throat, the human airway is composed of collapsible walls of soft tissue that can obstruct breathing. mild occasional sleep apnea, such as many people experience during an upper respiratory infection, may not be significant, but chronic severe obstructive sleep apnea requires treatment to prevent low blood oxygen (hypoxemia), sleep deprivation, and other complications. individuals with low muscle-tone and soft tissue around the airway (e.g., because of obesity) and structural features that give rise to a narrowed airway are at high risk for obstructive sleep apnea. the elderly are more likely to have osa than young people. men are more likely to develop sleep apnea than women and children are, though it is not uncommon in the last two population groups. the risk of osa rises with increasing body weight, active smoking and age. in addition, patients with diabetes or "borderline" diabetes have up to three times the risk of having osa. common symptoms include loud snoring, restless sleep, and sleepiness during the daytime. diagnostic tests include home oximetry or polysomnography in a sleep clinic. some treatments involve lifestyle changes, such as avoiding alcohol or muscle relaxants, losing weight, and quitting smoking. many people benefit from sleeping at a 30-degree elevation of the upper body or higher, as if in a recliner. doing so helps prevent the gravitational collapse of the airway. lateral positions (sleeping on a side), as opposed to supine positions (sleeping on the back), are also recommended as a treatment for sleep apnea, largely because the gravitational component is smaller in the lateral position. some people benefit from various kinds of oral appliances such as the mandibular advancement splint to keep the airway open during sleep. continuous positive airway pressure (cpap) is the most effective treatment for severe obstructive sleep apnea, but oral appliances are considered a first-line approach equal to cpap for mild to moderate sleep apnea, according to the american academy of sleep medicine (aasm) parameters of care. there are also surgical procedures to remove and tighten tissue and widen the airway. snoring is a common finding in people with this syndrome. 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. stroke is associated with obstructive sleep apnea. obstructive sleep apnea is associated with problems in daytime functioning, such as daytime sleepiness, motor vehicle crashes, psychological