It seems everywhere you look someone is dunking themselves in ice-cold water. Lizzo plunges to help with inflammation, Amy Poehler swears by her daily dunk, and Bradley Cooper even posed for a magazine shoot at his favourite dipping hole.

In THE PLUNGE, intrepid journalist Chris Ballard immerses himself in this growing tribe of cold-water junkies of all ages, shapes and nationalities, meeting social circles and those trying to create a new Olympic sport. He travels to laboratories and swims in waters around the world, from Portsmouth to the Pacific, exploring evolutionary principles and ancient practices largely lost in the modern world.

From cold plunge to open water swimming to ice swimming, he tests his limits in this extreme sport, eventually becoming a US national champion in the Ice Mile -- a mile-long swim in freezing water, a test of body and mind.

Along the way, he explores the cutting-edge science of the benefits of cold water: how it helps with muscle recovery and soothes chronic pain, boosts feelings of alertness, contentment and energy, and can even help to treat depression and anxiety.

THE PLUNGE is a rollicking, eye-opening adventure about the cure that's freely available to all and as old as the planet itself: cold water.