Rapid eye movement sleep, which should be referred to as rapid eye movement sleep (REM), is a state of sleep that is also known as rapid wave sleep because the brain waves at this time show low amplitude fast waves, similar to those at the time of awakening. It is also called heterophasic sleep because the brain waves at this time show active cortex and are actually in a sleep state. Sleep is divided into light sleep period, light sleep period, middle sleep period, deep sleep period, and rapid eye movement period, and these periods alternate to form a sleep cycle, and generally middle sleep period, deep sleep period and rapid eye movement period are more helpful to relieve fatigue and restore physical condition. The REM phase is characterized by hyperalgesia, muscle relaxation, reduced sympathetic activity and hypothalamic thermoregulation. The tachycardia period retains some intermittent, paroxysmal body twitching and rapid eye movement, and may include rolling over and eye rolling, as well as increased blood pressure, increased heart rate, and shallow and rapid irregular breathing, which are more likely to be awakened. In addition, dreams are often formed during this stage of sleep. 74%-95% of the population has dreams during this stage of sleep, but only about 7% of the population can clearly recall the dream scene. These symptoms may also be associated with nocturnal episodes of diseases such as asthma, angina pectoris, and pulmonary hypoxic attacks. Increased brain protein synthesis, increased oxygen consumption and blood flow, and reduced growth hormone secretion during the REM period can promote energy recovery and memory storage, thus improving learning and productivity the next day. Therefore, if you are chronically in a situation where the duration of the tachycardia period is insufficient, it may lead to memory loss.