"A good mother announced a litany of things to be avoided during menstruation: excessive exercise, hot and cold baths, wet feet. (The ever-popular "gym excuse" is a remnant of this idea that a girl has to be especially careful during menstruation.) (Brumberg 36)."
Since we're currently working on the hypothesis that we are cycle-syncing over the Internet, illustrator I Heart Guts' menstrual flow-chart is both handy and topical. Legends like "Day 13: HORMONE PARTY!" and "LUTEAL LUNACY!" make bleeding seem...fun.