Persons with sleep apnea have a 30% higher risk of heart attack or death than those unaffected. In severe and prolonged cases, increased in pulmonary pressures are transmitted to the right side of the heart. This can result in a severe form of congestive heart failure known as cor pulmonale. Diastolic function of the heart also becomes affected. Elevated arterial pressure (i.e., hypertension) can be a consequence of OSA syndrome. When hypertension is caused by OSA, it is distinctive in that, unlike most cases (so-called essential hypertension), the readings do not drop significantly when the individual is sleeping (non-dipper) or even increase (inverted dipper).Without treatment, the sleep deprivation and lack of oxygen caused by sleep apnea increases health risks such as cardiovascular disease, aortic disease (e.g. aortic aneurysm), high blood pressure, stroke, diabetes, clinical depression, weight gain, obesity, and even death. OSA is associated with cognitive impairment, including deficits in inductive and deductive reasoning, attention, vigilance, learning, executive functions, and episodic and working memory. OSA is associated with increased risk for developing mild cognitive impairment and dementia, and has been associated with neuroanatomical changes (reductions in volumes of the hippocampus, and gray matter volume of the frontal and parietal lobes) which can however be at least in part reversed with CPAP treatment. Epidemiology
Until the 1990s, little was known regarding the frequency of OSA.
Therefore, nocturnal symptoms indicating the presence of OSA (e.g. snoring, gasping, restless sleep and excessive energy used to breathe during sleep) are associated with daytime symptoms such as concentration and learning difficulties and irritability, neurocognitive development impairment, decreased school performance and behavioral difficulties. For example, SDB such as OSA contributes to hyperactive behavior that can lead to the diagnosis and treatment of attention deficit hyperactivity disorder (ADHD). However, once the SDB is treated, the hyperactive behavior can improve, and the treatment can be stopped. Obesity also has an impact on the consequences of OSA and lead to different manifestations or severity. Studies have shown that, contrary to adults, children with obstructive sleep-disordered breathing are able to maintain cerebral oxygenation. However, the condition still has effects on the brain and can lead to adverse neurocognitive and behavioral sequelae. It is particularly concerning as those consequences happen while the brain is still developing. The degree to which the sleep is disturbed and fragmented has been significantly linked to the severity of the consequences, the latter having the possibility to decrease once the sleep is improved. It is more the disruption of sleep processes than the total amount of sleep the child experience that generates the adverse consequences on the childs daytime functioning; it contributes to the hyperactivity for example.Children with OSA may experience learning and memory deficits and OSA has also been linked to lowered childhood IQ scores.