Your menstrual cycle is more than a monthly event—it’s a feedback system. Hormones like estrogen and progesterone are constantly responding to inputs: how you eat, how you train, how you sleep, and how stressed you are. When you understand this, the goal shifts from “managing symptoms” to actually working with your physiology—adjusting nutrition, exercise, and even fasting to match each phase of your cycle. Phases in a woman's menstrual cycle and the hormones that play a role