Sleep is so important to living organisms that sleep deprivation in mice can cause most otherwise healthy mice to die within a week, and examples of sudden death in young people due to reduced sleep abound. Most people sleep 6 to 8 hours a night, which consists of 4 to 5 sleep cycles. Each sleep cycle contains two components, one known as the non-REM sleep phase and the other known as the REM sleep phase. The REM sleep phase is more important for nerve growth and repair in the brain, and it is the REM sleep phase that is the first to be replenished after a long period of sleep deprivation. REM sleep is a special state of sleep in which the body’s brain waves and blood pressure and heart rate behave much like those of waking hours, often with clear and vivid dreams, and if a person is awakened at this time, he or she will remember the dream very clearly. In this sleep phase, muscle tone is inhibited, so no dream-related movements occur. If the mechanism that inhibits muscle tone is impaired, the person may experience dream-related behaviors that are often harmful, a condition known as RBD (rapid eye movement behavior disorder). The most central symptom of RBD in terms of clinical presentation is the occurrence of dream-related behaviors. For example, in the dream state, the person is fighting with someone, and in reality, there is a boxing or stomping action, which may cause injury to the person or bed partner. Other manifestations include dream-talking, laughing, yelling, cursing; complex behaviors including saluting, shaking hands, swatting mosquitoes, throwing quilts and pillows, and the possibility of the patient himself falling out of bed onto the floor. Patients are often awakened by their behavior, and at the time of awakening, the dream they just had is mostly clearly remembered. Other disorders may have similar manifestations to RBD, such as night terrors and sleepwalking, but these two abnormal sleep behaviors occur in the non-rapid eye sleep phase, and the patient wakes up with no memory of the previous behavior or dream. The most reliable method of diagnosing RBD and differentiating it from other sleep disorders is sleep monitoring, which requires a sleep monitoring device called a polysomnograph (PSG). In the fast-acting eye sleep phase, the human brain requires inhibition of muscle tone, and it is currently believed that this center is primarily in the pontine brain (a primitive structure in the lower posterior part of the brain). In children and adolescents, the incidence of sleep abnormalities is relatively high, and some of them can also have RBD, which is a result of imperfect brain function. However, if the problem occurs in adulthood after the original absence of RBD, it needs to be taken seriously, indicating that there may be abnormalities in the corresponding areas of the pontine brain. If the abnormality appears suddenly, it may be caused by cerebrovascular disease or inflammation or trauma; if the abnormality appears gradually, and the frequency and severity of the abnormality are increasing year by year, you should be concerned about chronic neurodegenerative diseases, or neurodegenerative diseases as they are scientifically called, Alzheimer’s disease (also called Alzheimer’s disease, dementia) and Parkinson’s disease (folk like to call it shaking disease) are the most common neurodegenerative diseases. The most common neurodegenerative diseases are Alzheimer’s disease (also known as Alzheimer’s and dementia) and Parkinson’s disease (folk like to call it jitters). However, due to the disease mechanism, RBD is generally not associated with Alzheimer’s disease, but more closely with Parkinson’s disease and other less common diseases such as multiple system atrophy and Lewy body dementia. It is believed that 50-70% of patients with RBD may develop neurodegenerative diseases such as Parkinson’s disease 10-15 years later. Especially when RBD is associated with symptoms such as decreased sense of smell, decreased ability to recognize colors, and constipation, the likelihood of developing neurodegenerative diseases such as Parkinson’s disease becomes high several years later. If this is the case, you should be alerted and seek early consultation at a specialized hospital that is capable of diagnosing and treating this disease. REM sleep is very important for the repair and growth of brain nerves, and REM sleep behavior disorder is one of the warning signs of more serious diseases, and is also harmful in itself.