Hello welcome to health care magic and thanks for your question. No, physical exercise generally doesn t cause vaginal bleeding Irregular bleeding might be related to number of gynecological conditions like hormonal imbalances, Infection or PID endometrial disease, stress and anxiety and many other rare causes. In my opinion you should visit a gynaecologist as per your convenience for physical examination, colposcopic examination and series of investigation including hormonal assessment and ultrasound if need be. oral contraceptive pills also help in regularisation of menses, however you should consult a gynaecologist for further course of action. meanwhile maintain good hygiene, have lots vof green leafy vegetables and iron and multivitamin supplements if you have lost a significant amount of blood during periods. Hope this answers your question, please do let me know if you have any more queries, I will happily answer you. Best wishes