Boost your performance by increasing your COâ‚‚ tolerance
Your body’s ability to tolerate carbon dioxide has a direct impact on how efficiently you use oxygen. As COâ‚‚ levels rise in your system, blood vessels dilate, circulation increases, and oxygen delivery to your muscles improves. At the same time, hemoglobin releases oxygen more readily – exactly when your body needs it most.
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Higher COâ‚‚ tolerance means:
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your muscles stay in aerobic energy production for longer
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your performance becomes more efficient and sustainable
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recovery improves as blood flow remains strong
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your system stays calmer even under heavy load
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Breath-hold training allows you to develop this ability quickly and safely. The book doesn’t include a sport-specific program, but it contains practical exercises adapted from the world of freediving – designed to help you increase your COâ‚‚ tolerance in a controlled way.
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Once you understand the physiology and try it for yourself, you can easily incorporate breath-hold exercises into your existing training – in a way that fits your needs.
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Order the book and make breat holding exercises part of your training.
Carbon dioxide helps your muscles work better – for longer
When COâ‚‚ levels rise in your body, it's not a threat – it's what allows your muscles to use oxygen more effectively. The increase in carbon dioxide slightly lowers blood pH, which in turn makes hemoglobin release oxygen more easily to working muscles. This is known as the Bohr effect – your body’s built-in mechanism for optimizing oxygen delivery when it's needed most.
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As a result:
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your muscles stay in aerobic metabolism for longer
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oxygen and nutrient delivery improves
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your entire system functions more efficiently under load
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Breath-hold training raises COâ‚‚ levels in a safe, controlled way. It also helps your body adapt to this natural – but often uncomfortable – state. The better you tolerate carbon dioxide, the more you can benefit from its performance-enhancing effects.
By reading the book, you'll understand how this physiology works.
By doing the included exercises, you can improve your COâ‚‚ tolerance quickly and effectively.
Train like you’re at altitude – anytime, anywhere
When your body is exposed to elevated COâ‚‚ and mild oxygen deprivation, it responds in much the same way as it does at high altitude. Thinner air and reduced oxygen trigger adaptations that improve both oxygen delivery and utilization – exactly the traits needed for endurance performance.
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Breath-hold training creates a similar physiological stimulus:
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oxygen saturation drops in a controlled way
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COâ‚‚ levels rise gradually
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the body adapts to a state where oxygen must be used with maximum efficiency
This kind of “altitude training” can be activated anytime – no travel, no special equipment. The exercises are short, simple, and easy to integrate into your training routine. They won't replace your workouts, but they can greatly enhance your body's ability to handle stress and adapt more effectively.
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By understanding what’s happening in your system – and giving your body the right kind of stimulus – you can build physiological traits that show up directly in your performance.
Why practice breath holding?
When you train breath-holding, you learn to breathe better – deeper, slower, and more efficiently. You begin to use your lungs to their full capacity. This is not only important for performance – it also increases body awareness, presence, and peace of mind in daily life.
Breath-holding is a powerful and versatile practice that benefits both body and mind. When done regularly, breathing and apnea exercises strengthen the muscles of the respiratory system – especially the diaphragm and chest muscles – improving lung capacity and breathing efficiency.
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Breath-holding also increases your body’s ability to tolerate higher levels of carbon dioxide. As COâ‚‚ builds up, blood vessels dilate and circulation improves. This enhances the delivery of oxygen and nutrients to the muscles, improving endurance, performance, and recovery. A higher COâ‚‚ tolerance also helps maintain the body’s optimal pH balance, making oxygen more available for use in your muscles.
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Improving COâ‚‚ tolerance through breath-holding is one of the most effective ways to support overall well-being and athletic performance.
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Breathing exercises also have a deep mental dimension. Focusing on your breath promotes relaxation, reduces stress, and brings mental clarity. Breath-holding activates the body’s natural dive response, which helps conserve oxygen by quieting the brain’s “thinking center.”
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This oxygen-saving reflex makes freediving and breath-holding a uniquely calming and meditative practice – one that supports resilience, presence, and both physical and mental endurance in everyday life and demanding situations.
AUTHOR
Johanna Nordblad
ICE DIVING WORLD RECORD HOLDER
I’m a freediving instructor and a three-time world record holder. I’ve taught breath-holding to both beginners and elite athletes, and I’ve seen the powerful effects of simple exercises: calmness, confidence, endurance, and the joy of moving in water.
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I wrote this book because I believe breath-holding is a skill everyone should have – not just competitive divers. Training can be enjoyable, safe, and deeply relaxing.
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If you want to learn how to breathe properly, breath-holding is one of the easiest and most effective ways to do it.
You can learn more about me and my work in the Netflix documentary
“Hold Your Breath: The Ice Dive” (2022)
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Order the book now and start your journey into the world of breath.
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