“Early to bed, early to rise” has been well-regarded health advice since ancient times. An ancient Chinese saying says, “Work since sunrise and rest at sunset.” But why is sleep so important? The idea of activity beginning at sunrise and ending at sunset aligns with the laws of nature and the human body’s internal processes.
Three American scientists discovered a biological clock inside the human body, also known as the circadian rhythm. They also identified the key genes that control the biological clock, earning them the 2017 Nobel Prize in Physiology or Medicine. However, as early as 2,500 years ago, the Chinese medicine classic “The Yellow Emperor’s Canon of Internal Medicine” discussed the existence of this law, calling it “Zi Wu Liu Zhu (Midnight-noon and ebb-flow doctrine).”
