What do you mean, Yang flourishes and Yin declines, and there is no light for a day?

Yang flourishes and yin declines, and insufficient light during the day means weakness. According to relevant public information, yin deficiency in TCM refers to deficiency of yang, or deficiency of yang caused by yin, resulting in symptoms such as chills, cold limbs, bowel sounds and diarrhea. Yang hyperactivity due to yin deficiency is a relative manifestation of Yang hyperactivity due to yin deficiency, with symptoms such as backache and leg weakness, dizziness and tinnitus, fever, hot flashes and night sweats.