A Book by Erik Berggren
SAUNA LIKE
A VIKING
IN THE QUEST TO LIVE TO A HUNDRED
What if one of the most powerful tools for living longer, thinking clearer, recovering faster, and feeling stronger has been hiding in plain sight for centuries?
The science-backed benefits of sauna and cold plunge therapy
How heat and cold exposure support longevity and cardiovascular health
Simple sauna protocols for recovery, performance, and stress reduction
Why Nordic cultures treat sauna as a foundational health practice
How to combine cardio training, recovery, and resilience for long-term vitality
The role of discipline, discomfort, and adaptation in living a stronger life
Practical routines you can implement regardless of age or fitness leve
For generations, Nordic cultures have embraced sauna and cold exposure as a way of life — building resilience, improving health, and extending vitality deep into old age. In Sauna Like A Viking, Erik Berggren combines ancient tradition with modern longevity science to show how heat, cold, movement, and recovery can dramatically improve the way you age.
Whether you're an athlete, wellness enthusiast, biohacker, or simply someone who wants to feel better and live longer, Sauna Like A Viking offers a straightforward roadmap rooted in both tradition and evidence.
You don't need extreme routines or complicated systems to improve your future health. Sometimes the answer starts with heat, cold, and the willingness to embrace discomfort — like a Viking.
Free Download — The Viking Forge Protocol PDF
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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
The Viking Forge Protocol
THREE CYCLES OF HEAT.
AT LEAST TWO COLD SHIVERS.
One cycle is a warm room. Three cycles is the Forge. The biology requires the repetition — the first cycle opens the system, the second drives it deeper, the third seals it. Between them, the cold shiver activates the body's deepest metabolic response.
Cycle I
The Softening
Enter the heat. Reach your limit.
Not your comfortable limit. Your actual limit. The first cycle is typically the longest — your body is coming from ambient temperature. Follow the signal, not the clock. Thermal Load target: 125-135 (temperature C + humidity %). Then take the first cold shiver — full immersion until the shiver builds and the brown adipose tissue ignites.
70-80C / 55-65% humidity
Cycle II
The Deep Forge
Back into the heat. Then the second shiver.
The second heat phase drives deeper. Your body is already primed — the blood vessels are open, the heart rate elevated, the heat shock proteins mobilised. Return to the cold for the second shiver. This is the signal. It means your metabolic furnace has switched from standby to full output. No towel. Let the shiver take hold.
5-12C cold immersion
Cycle III
The Final Seal
The work is done. The forge is complete.
The third heat phase is meditative. The slag has been purged. What remains is a deep, still heat. Stay until the heat feels like a heavy blanket you can no longer carry. The session is complete when the sweat stops regardless of hydration.
Three cycles minimum
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Advance Review Copy
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We are distributing advance review copies of Sauna Like a Viking ahead of launch.
The only ask is an honest Amazon review prior to launch day as per the instructions included with your advance review copy.
Limited to the First 100 Copies
Limited to 100 copies. An honest review is the only ask.
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.
Swedish Navy Combat Veteran
World Cup Mountain Biker
MSc Advanced Finance, Uppsala University
Certified Sailing Captain
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."
Press & Media
For journalists,
podcasters & reviewers.
One cycle is a warm room. Three cycles is the Forge. The biology requires the repetition — the first cycle opens the system, the second drives it deeper, the third seals it. Between them, the cold shiver activates the body's deepest metabolic response.
Book Synopsis
A full synopsis of Sauna Like a Viking, including the book's argument, structure, target audience and chapter overview.
Author Biography
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Interview or
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