When the cold water hits the surface of your skin, the blood from deep inside the body rushes to the surface in self-defense. All of the capillaries open up, clearing deposits and toxins, while also improving circulation. When the blood returns from the surface, a freshly circulated blood supply goes back to the organs. As the cold persists, Ishnaan sets off the release of cytokines, small cell-signaling protein molecules that are used extensively in intercellular communication, assisting in development, tissue repair, and immunity. It also triggers an avalanche of endorphins. Oh, the beautiful endorphins.