Lack of sleep caused by staying up late slows down the metabolism of brain cells, making the brain metabolize various wastes and toxins accumulated in the brain interstitium, and cannot be discharged. Long-term can cause the human body thinking and reaction, learning and cognitive ability are reduced, that is, the daily people say stupid, while long-term stay up late can increase the occurrence of a variety of diseases. Studies have shown that when the human body is in deep sleep, the brain is still working, and compared to the daytime work more efficient, blood flow is faster, providing more oxygen to the brain, while the brain can be flushed between the interstitial waste and toxins, making the brain more clean. When waking up from sleep, the brain is rich in blood supply and oxygen supply and can carry out normal daytime activities. However, long-term staying up late can accelerate brain cell damage and apoptosis, which can easily cause daytime mental discomfort, fatigue, immune decline, memory loss, and decreased comprehension, which can indirectly lead to diseases such as colds and depression, and serious cases may have neurological diseases such as Alzheimer’s and Parkinson’s. In addition, the lack of sleep caused by long-term late night can also affect the function of the body’s organs and increase the risk of diabetes, hypertension and other diseases. Therefore, it is recommended that adults get enough sleep on a daily basis to help keep their energy levels high during the day and improve their work and study efficiency. At the same time, sufficient sleep can repair the part of the brain that manages emotions, maintain emotional stability and reduce the occurrence of bad moods.