Recommendation

This was a good book. I’ve struggled to keep up a practice of meditation, but I find that breathwork is a good way to keep my meditation practice up. With breathwork I can strive for things like longer breath hold times, lower resting heart rate, and imrpoved cardio performance.

I listened to this book as an audio book, and the appendix had some narrated breathing exercises. For this reason, I would recommend listening to the audiobook.

My thoughts

This was a great companion to the other book I just finished What Doesn’t Kill Us. It briefly mentions Wim Hof, but provides a much broader overview of techniques for breath control.

Weight loss

There was a fact in this book that caught me off guard because of how obvious it is; and yet, I had never actually thought about it. When we lose weight, the weight has to go somewhere, and the majority of the weight we lose is exhausted as CO2. Another significant portion is lost as sweat.

CO2 concentrations

When we feel the urge to breath after holding our breath, the source of that signal is not how much oxygen we have, but how much CO2 we have. This leads to some pretty interesting observations and tests. If we breath CO2-enriched air, even if the oxygen levels are fine, our bodies will rebel and tell us that we’re dying. This even induced panic attacks in humans who were missing the fear-center in their brain.

But knowing this means that we can improve our aerobic fitness and the length of breath holds by practicing with CO2 enriched air. It also helps just knowing more about the body’s natural response to things - it makes the physical responses less scary.

Mouth breathing

The book claims the the most important piece of advice that it has to offer is:

Shut your mouth

Mouth breathing has very negative, measurable impacts on health. I’ve experienced the bad breath and parched feeling in the morning knowing that I must have had my mouth open, but I did not realize how many other parts of the body it affected.

Our ancestors

There are lots of claims in the book that our ancestors were much less congested and had fewer mouth problems than we are. I think there is likely strong direct evidence for them having better mouths because teeth can be found with skulls, and I appreciated the lining up of evidence for our ancestors being less congested.

The evidence lines up as follows:

• We have skulls of our ancestors
• We know that modern humans with those skull shapes tend to have less congestion
  • Humans with worse skull shapes have seen improvements in congestion correlated with a change in skull shape using orthodontic equipment
  • Humans born with better skull shapes tend to have less congestion