Of course she can be as active as the other days. The important thing is to listen to your body and do exactly what you feel. If, for example, you feel weakness and you have a heavy flow and all you want to do is stay home and rest, this is what you should do. Likewise, if you feel full of energy and in the mood for sports, there is absolutely no reason not to work out. At the same time if you feel pain, exercise will improve your blood circulation and the secretion of endorphins, will help you considerably to feel better.