A Book by Erik Berggren

SAUNA LIKE

A VIKING

IN THE QUEST TO LIVE TO A HUNDRED

The 1,000-year-old heat-and-cold practice for a longer, stronger life. The science, the protocol, and the Nordic tradition I grew up with — in one field manual.

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Prefer a physical copy? The print edition is available on Amazon.

The Book

NOT A WELLNESS BOOK.

A FIELD MANUAL.

It begins with a phone call. Stage 4 Hodgkin's Lymphoma. Seventy percent chance of survival. The author's younger brother, calling on the night before a mountain bike race. That call ended a career spent chasing trophies and began something more serious — a decades-long pursuit of a system for living at full capacity, for as long as possible.

The sauna and the cold plunge are at the centre of that system. This book explains why, and exactly how to use them. The science is peer-reviewed. The protocol is specific. The history spans every civilisation that ever survived a hard world.

Hot and cold therapy is at the core of living to a hundred. The repeated cycle of thermal stress and cold exposure triggers the body's deepest repair mechanisms — heat shock proteins that protect and rebuild cells, cold-activated norepinephrine that sharpens the mind and burns dormant fat, and a cardiovascular workout that rivals distance running without a single step. Every civilisation that produced centenarians understood this. The Finnish, the Japanese, the Romans, the Scandinavians — they all built rooms of heat. The science now confirms what they knew by instinct: the forge of hot and cold is the closest thing we have to a longevity protocol that costs almost nothing and works for almost everyone.

With tales from the north — true modern viking stories from today — woven throughout, including guest chapters by Erik's sister Kajsa and his brother Anders, who rebuilt his life after cancer around three principles: a sauna always warm, a table big enough for everyone, and food with a story.

Scientific Validation for the Ongoing Sauna Practice

The Heart

Cardiovascular conditioning and vascular resilience through thermal stress

Metabolism

Insulin sensitivity and brown adipose tissue ignition

Cellular Repair

Heat shock proteins, autophagy, and senescent cell clearance

The Mind

BDNF production, cognitive protection and neuroprotection

"The most practical and rigorous book on sauna and cold therapy I have read. Erik's voice is unlike anyone else writing about longevity."

— Josh Fly

About the Author

ERIK

BERGGREN

Viking by birth. American by calling.

He grew up at the base of a mountain in northern Sweden, in a world built on cold, endurance, and the quiet pride of people who do hard things without making a fuss about it. The sauna was as natural as breakfast. The cold was not something you avoided. You simply went outside. He carries that with him everywhere he goes, and he always will. When Sweden lines up at the start of a ski race or skates onto the ice at a World Championship, he still bleeds yellow and blue. That part does not change with a passport.

He served in combat with the Swedish Navy at nineteen. Competed in mountain biking at World Cup level. Graduated top of his class in Advanced Finance from Uppsala University. Spent three decades building, buying, and scaling more than thirty companies across Europe and the United States — including an eight-figure AI deal with one of the world's top three technology companies.

"The culture forged me. It also constrained me. I understood early that my spirit was built for somewhere else — not in rejection of where I came from, but in recognition that the specific hunger I carried needed different soil to grow in."

© 2026 Erik Berggren. All rights reserved.