How did this become a thing?!

Cold plunge therapy, or cold water immersion, is an ancient practice with deep historical roots in various cultures and civilizations across the world. 

Early mentions of therapeutic cold applications can be traced back to ancient Egypt and the Edwin Smith Papyrus, dating back to 3500 BC. 

In ancient Greece, Hippocrates, often considered the "father of medicine," advocated for the use of cold water to treat fever and fatigue, while the Greeks used cold baths for athletic training and recovery. The Romans further popularized the practice with their elaborate bathhouses, which often included frigidariums (cold rooms with plunge pools) for a refreshing and health-promoting experience.