Reason:

First of all, 5-7 o'clock is the season of the large intestine meridian, which is the defecation time. Drink a cup of warm water after getting up, take a walk and defecate.

Secondly, the sun will also rise. When people get up, the yang will increase, which is beneficial to their health. (This is the sunrise, and the Taoist way of keeping in good health is natural. )