Do sports during the period increase flow of blood?

Depends. In general, women who are athletic and participate in sports have lighter periods overall. Actively participating in sports including high impact activity during a heavy flow might increase the flow somewhat, whereas resting with the feet up may seem to slow things down. If heavy flow is interfering with sports, using birth control pills, lysteda, or Ibuprofen or Aleve (naproxen) may help.