Repeated apnea during sleep can lead to high and low oxygen in the body, and intermittent hypoxia is damaging to several organs. Moreover, because it is necessary to wake up from deep sleep in order to save oneself during apnea, deep sleep is significantly reduced and sleep is fragmented. If this persists it can cause very serious damage to several systems and even sudden death. The cardiovascular system includes hypertension, heart failure, arrhythmia, coronary artery disease, and pulmonary hypertension; the nervous system includes stroke, cognitive decline, and neurodegenerative disease; the digestive system includes gastroesophageal reflux; and the endocrine system includes obesity, diabetes mellitus, and dyslipidemia. In addition, the risk of anesthesia during surgery is very high in these patients, and the possibility of asphyxia is relatively high, with more postoperative complications.