When the north wind of the cold winter howls past, the earth is covered with frost and snow. People wrap themselves tightly in cotton-padded clothes and hide in warm rooms, fearing that even a hint of cold might invade their bodies. In such a season, when the three words "ice bathtub" are mentioned, many people would probably gasp in astonishment and even blurt out, "Are you crazy?" However, it is precisely in such a harsh season that there is still a group of people who choose to step into a bathtub filled with ice water and have a dialogue with the extreme cold through their bodies. So, would you dare to use an ice bathtub in winter?