If a woman exercises vigorously before her period, it can lead to early menstruation. First, because the uterus and cervix are congested before the onset of menstruation. If you exercise a lot at this time, the endometrium will flake and bleed prematurely, which will lead to early menstruation. Secondly, the hypothalamus is inhibited by vigorous exercise, which leads to endocrine disorders and abnormal secretion of estrogen, leading to early menstruation. Finally, if the body is weak and there is deficiency of qi and blood, the body will become even weaker after strenuous exercise, which will lead to early menstruation. Therefore, women can exercise in moderation before and after their menstruation, and they need to take rest and avoid straining. Strenuous exercise is not recommended to avoid adverse effects on menstruation or even aggravate the symptoms of dysmenorrhea.