The biological clock is an innate human tool that keeps us essentially on a 24-hour behavior cycle, with regular intervals between sleeping and eating. In fact, everyone’s biological clock is not the same and it can deviate. Some people will go to bed late but sleep until they get up in the afternoon; some people go to bed early but wake up early; some people sleep for a short time, less than 5-6 hours a day, but have a lot of energy; some people sleep for a long time but are still lethargic. Interestingly, sometimes within entire families, many people have similar deviations in their biological clocks. Some diseases show more pronounced changes in sleep and biological clocks, such as depression often waking up at 2 or 3 a.m. These are now thought to be genetically linked. For example: Early to bed and early to rise has long been considered a recipe for healthy living, but early to bed and early to rise, an accepted healthy routine, can also be a condition called familial hypersleep syndrome, in which people who suffer from this condition go to bed and wake up 3-4 hours earlier than the average person. For some people who love to get up early, going to bed early and waking up early is actually the result of a genetic mutation. Studies have found that patients who sleep early and wake up early have mutations in the PERIOD2 gene. It is generally believed that the less phosphorylated the modified PERIOD2 protein is, the more stable it is, although the opposite is true in these patients. The mutated protein was degraded at more than twice the normal rate. The scientists claim that this is the first case of human behavior that can be truly explained at the protein level.