How long does cold water stop your menstruation cycle?

Water doesnt really stop your mentration cycle, it just decreases the flow to almost none. WHen a woman gets into [contact with] cold water, the muscles in the lower abdomen tighten, decreasing the blood flow to very little. It's still there, but little enough to seem invisible or stopped. And i think, it takes a minute or less to get the blood flowing out again once a woman gets out of cold water.