Why is the period delayed?

The establishment and maintenance of normal menstruation depends on the neuroendocrine regulation of the hypothalamic pituitary ovarian axis and the periodic response of the target organ endometrium to sex hormones and the patency of the lower reproductive tract. Here, any obstacle in any link will cause menstrual disorders. Fitness belongs to exercise type amenorrhea, and long-term intense exercise is easy to cause menstrual disorders. The maintenance of menstruation depends on a certain proportion of body fat, if the ratio of muscle and fat increases or the overall fat decreases, it will make menstruation abnormal. Moreover, after intense exercise, the gonadotropin released by the hypothalamus will be suppressed, which will also cause menstrual disorders. Therefore, excessive fitness will cause menstrual disorders.