If there is a lack of energy during menstruation, it is mainly related to changes in hormone levels in the body. 1. Due to individual differences, estrogen and progesterone decline during menstruation, and some people are relatively sensitive to this decline in hormone levels, so they will show a lack of energy, fatigue and drowsiness during menstruation. 2. In the clinic during menstruation must pay attention to proper rest, if there is no diabetes can drink hot brown sugar water to replenish energy to relieve this uncomfortable feeling. 2, in the clinic in the case of a particularly large amount of menstruation, it will lead to the appearance of a short period of anemia, but also a lack of energy in the whole body, so it is necessary to give a distinction. Clinically, if the menstrual flow exceeds 80ml, it is considered excessive menstruation, and clinical examination is needed to understand the causes of excessive flow and to give appropriate treatment.