Staying up late is a Chinese term that is scientifically considered to refer to shift work involving disrupted circadian rhythms that interfere with sleep. Therefore, staying up late is a break in sleep. Good sleep means a regular biological clock and sufficient sleep time, and staying up late breaks the biological clock, which can lead to endocrine disruption and reduced sleep time, or staying up all night can aggravate physical fatigue. In other words, no matter what time you go to bed, as long as you maintain a fixed sleep cycle and relatively stable sleep duration, it is not strictly speaking considered to stay up late. For example, if a person goes to bed at 4:00 a.m. and gets up at 12:00 p.m. every day, his biological clock has been adjusted to the 8 hours of sleep from 4:00 a.m. to 12:00 p.m. and keep the regularity, it actually cannot be considered staying up late. But if you often do not go to bed at a fixed time, and less sleep, is to stay up late.