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.
Believe nothing you cannot verify for yourself, Son.