Lifelong athlete and Sports Illustrated writer Chris Ballard worried his days of exercise were numbered. Then he received a fateful text message about a trend taking hold around the world: submerging in freezing cold water.

It wasn’t only thrill seekers or wellness gurus extolling its power. Swimmers have long known that when paired with cold, their sport delivers extraordinary rewards; now, modern research has shown that just a few minutes in cold water can deliver remarkable benefits: heightened energy and focus, reduced inflammation, and relief from depression and anxiety.

In The Plunge, Ballard travels to laboratories and swims in waters around the world, from Portsmouth to the Pacific, tracing the roots of cold water swimming in ancient practices largely lost in the modern world.

He immerses himself in the growing tribe of cold-water junkies of all ages, shapes and nationalities, from pioneers like Lynne Cox to visionaries like Ram Barkai, whose audacious dream of getting ice swimming into the Olympics edges closer to reality.

And, from cold plunging to open water swimming to ice swimming, he tests his limits in this extreme sport, eventually becoming a US national champion, his body and mind transformed along the way.

Blending history, cutting-edge science, colourful characters, and propulsive narrative storytelling, it’s a rollicking, eye-opening adventure that reveals how a single act ― stepping into cold water ― can unlock resilience, connection, meaning and joy.