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Hotwired: How the Hidden Power of Heat Makes Us Stronger – A Science-Based Guide to Heat Adaptation, Sweat Therapy, and Peak Performance
From the #1 New York Times bestselling coauthor of Outlive comes a radical exploration of the science of heat adaptation and sweat therapy to tap into the evolutionary superpowers that we’ve forgotten we possess.
What if the key to thriving in a hotter world isn’t avoiding the heat—but harnessing it?
In Hotwired, bestselling author and science journalist Bill Gifford takes readers on a fascinating exploration of the power of heat to improve our performance and our health. Combining cutting-edge science, personal discovery, and practical insights, Gifford reveals how heat adaptation and heat therapy such as sauna can make us healthier, stronger, and even happier, by unlocking the body’s built-in tools to promote longevity and resilience.
Through innovative research in evolutionary biology, physiology, and thermoregulation, Gifford uncovers how humans evolved to excel in sweltering conditions—and how we’ve lost touch with this ancient advantage. He plunges into the steamy world of Finnish saunas, serves as a test subject in cutting-edge heat labs, and tackles a grueling 100-mile bike ride under the blazing Texas sun—to show how temperature extremes can expand our physical and mental limits. He even explores how infrared sauna therapy may fight depression more effectively than medication—and how many people are rediscovering the power of communal wellness through the use of social sauna.
Whether you’re looking to perform better, extend your healthy lifespan, adapt to a warming planet, or tap into the human connection that forms when we sweat together, Gifford reveals the incredible benefits of reawakening your body’s natural adaptability to heat and cold. You’ll discover how sweat is more than a cooling mechanism; it’s central to peak performance. We were born to sweat, and sweating makes us stronger.
Hotwired shows how short-term discomfort transforms into long-term power. It’s a thrilling call to reimagine heat—not as a threat, but as a tool for survival and strength.
What if the key to thriving in a hotter world isn’t avoiding the heat—but harnessing it?
In Hotwired, bestselling author and science journalist Bill Gifford takes readers on a fascinating exploration of the power of heat to improve our performance and our health. Combining cutting-edge science, personal discovery, and practical insights, Gifford reveals how heat adaptation and heat therapy such as sauna can make us healthier, stronger, and even happier, by unlocking the body’s built-in tools to promote longevity and resilience.
Through innovative research in evolutionary biology, physiology, and thermoregulation, Gifford uncovers how humans evolved to excel in sweltering conditions—and how we’ve lost touch with this ancient advantage. He plunges into the steamy world of Finnish saunas, serves as a test subject in cutting-edge heat labs, and tackles a grueling 100-mile bike ride under the blazing Texas sun—to show how temperature extremes can expand our physical and mental limits. He even explores how infrared sauna therapy may fight depression more effectively than medication—and how many people are rediscovering the power of communal wellness through the use of social sauna.
Whether you’re looking to perform better, extend your healthy lifespan, adapt to a warming planet, or tap into the human connection that forms when we sweat together, Gifford reveals the incredible benefits of reawakening your body’s natural adaptability to heat and cold. You’ll discover how sweat is more than a cooling mechanism; it’s central to peak performance. We were born to sweat, and sweating makes us stronger.
Hotwired shows how short-term discomfort transforms into long-term power. It’s a thrilling call to reimagine heat—not as a threat, but as a tool for survival and strength.
- GenresNonfictionHealth
320 pages, Kindle Edition
Published March 17, 2026
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Displaying 1 - 5 of 5 reviews
April 12, 2026
Five stars. Read it in two days.
Great book to understand the science behind sauna vs the pseudoscience.
Gifford balances three things really well: peer-reviewed research, cultural history, and his own experiences. He’s a good writer. Self-deprecating, curious, never preachy.
The myth-busting was great - “sweating out toxins”, hype on cold plunging, etc. Gifford clarifies what’s real from what’s marketing.
Great book. Quick read. Engaging.
Great book to understand the science behind sauna vs the pseudoscience.
Gifford balances three things really well: peer-reviewed research, cultural history, and his own experiences. He’s a good writer. Self-deprecating, curious, never preachy.
The myth-busting was great - “sweating out toxins”, hype on cold plunging, etc. Gifford clarifies what’s real from what’s marketing.
Great book. Quick read. Engaging.
Want to Read
February 5, 2026Won and received a copy through a Goodreads Giveaway!
April 17, 2026
Hotwired~~~~
I eagerly picked up Bill Gifford's new nonfiction book Hotwired: How.the Hidden Power of Heat Makes Us Stronger. He's a science writer in his fifties who wouldn't have thought about writing about our crucial need for heat acclimatization and therapy if it hadn't been for his long-time publishers suggesting he do so. The importance of challenging our thermoregulators like people did before, basically air conditioning is mostly overlooked or casually ignored until the last handful of years. He went on an investigation into saunas, hot tubs, hot yoga, and clinical trials for heat or heat and cold therapy and has never felt better in his cognitive and cardiac function. His mood is much uplifted too.
Gifford learned that you need to get your body temperature up to 101 degrees Fahrenheit for our beneficial heat shock proteins to develop and do things like kill the COVID virus, greatly help reduce chances of strokes and dementia, and decrease anxiety and depression.
I found the book fascinating. I don't know if a sauna would be safe for me with my incomplete spinal cord injury that makes me faint if I feel too warm from eating/digesting too much greasy stovetop-popped popcorn. I need to research this because heat acclimatization therapy would really loosen my tight muscles from spasticity.
If you want to try this therapy, read Hotwired first and realize that Gifford kept track of his body temp with a rectal thermometer in the clinics and some other way, I think, when he rode the Hotter 'n Hell Hundred in Texas in August 2023.
Gifford used to hate to sweat, but now he craves being able to do it. He can enjoy hot days when others are sheltered indoors and has the bike trails to himself. This experience has positively changed his life, to his amazement, and he urges his readers to become acclimatized to hot weather as the climate threatens us with terrible heat waves that lingers and extreme weather patterns are only increasing. We evolved to be able to handle extreme temps much better than any other creature, being the one with the most sweat glands, so we need to start sweating.
Highly recommended!
I eagerly picked up Bill Gifford's new nonfiction book Hotwired: How.the Hidden Power of Heat Makes Us Stronger. He's a science writer in his fifties who wouldn't have thought about writing about our crucial need for heat acclimatization and therapy if it hadn't been for his long-time publishers suggesting he do so. The importance of challenging our thermoregulators like people did before, basically air conditioning is mostly overlooked or casually ignored until the last handful of years. He went on an investigation into saunas, hot tubs, hot yoga, and clinical trials for heat or heat and cold therapy and has never felt better in his cognitive and cardiac function. His mood is much uplifted too.
Gifford learned that you need to get your body temperature up to 101 degrees Fahrenheit for our beneficial heat shock proteins to develop and do things like kill the COVID virus, greatly help reduce chances of strokes and dementia, and decrease anxiety and depression.
I found the book fascinating. I don't know if a sauna would be safe for me with my incomplete spinal cord injury that makes me faint if I feel too warm from eating/digesting too much greasy stovetop-popped popcorn. I need to research this because heat acclimatization therapy would really loosen my tight muscles from spasticity.
If you want to try this therapy, read Hotwired first and realize that Gifford kept track of his body temp with a rectal thermometer in the clinics and some other way, I think, when he rode the Hotter 'n Hell Hundred in Texas in August 2023.
Gifford used to hate to sweat, but now he craves being able to do it. He can enjoy hot days when others are sheltered indoors and has the bike trails to himself. This experience has positively changed his life, to his amazement, and he urges his readers to become acclimatized to hot weather as the climate threatens us with terrible heat waves that lingers and extreme weather patterns are only increasing. We evolved to be able to handle extreme temps much better than any other creature, being the one with the most sweat glands, so we need to start sweating.
Highly recommended!
April 13, 2026
A terrifically engaging read that speeds by but leaves you with a lot to think about. As in his earlier book “Spring Chicken,” Gifford puts himself under the microscope on the readers’ behalf — and to great effect. A quite funny, whip-smart primer on little changes most people can make in their lives to better move through a warming world. Highly recommended!
April 4, 2026
I enjoyed this one - good information on benefits of heat therapy. Liked that the author shared personal experiences.
Displaying 1 - 5 of 5 reviews