⭑⭑⭑½ (3.5/5 see book reviews)

Breath by James Nestor

I sleep with tape over my mouth now.

The idea of sleeping with tape over my mouth is to improve my nasal breathing. The author posits that practicing nasal breathing makes you a better nasal breather.

These tissues and muscles get “toned” to stay in this opened and wide position. Nasal breathing begets more nasal breathing.

– James Nestor, Breathe

He also cites a dentist whom he quoted as saying:

mouthbreathing contributes to periodontal disease and bad breath, and was the number one cause of cavities, even more damaging than sugar consumption, bad diet or poor hygiene.

– James Nestor, Breath

And while it’s clear that the “evidence” for these claims is some random dentist saying something offhand, I figured it’d be an easy experiment to try on myself with very little downside risk. So I did it. And now I do it. It’s embarrassing, but man can I breath through my nose like a champion now.

And the author tells me I really really should breathe through my nose:

Nasal breathing alone can boost nitric oxide sixfold, which is one of the reasons we can absorb about 18% more oxygen than by just breathing through the mouth

– James Nestor, Breath

Of course, no book on breathing would be complete without talking about Wim Hof and he features in later chapters. And the section about Hof is a microcosm of the bad science in the book.

In 2011, researchers at Radboud University Medical Center in the Netherlands brought Hof into a laboratory and started poking and prodding him, trying to figure out how he did what he did. At one point, they injected his arm with an endotoxin, a component of E. coli. Exposure to the bacteria usually induces vomiting, headaches, fever, and other flu-like symptoms. Hof took the E. coli into his veins and then breathed a few dozen Tummo breaths, willing his body to fight it off. He showed no sign of fever, no nausea. A few minutes later, he rose from the chair and got a cup of coffee.

– James Nestor, Breath

I noticed two things about the above passage in this order:

  1. It’s probably not legal or safe to inject humans with E. coli
  2. The passage oscillates between talking about E. coli endotoxin and E. coli

Sure enough, the study, The Influence of Concentration/Meditation on Autonomic Nervous System Activity and the Innate Immune Response: A Case Study mentions “endotoxima,” (which, I guess, is a protocol for injecting people with endotoxin that may be excreted by E. coli bacteria), but not injecting people with E. coli as the book would suggest.

Anyway, the book has compelling parts, but hurts its own arguments with sloppy pseudo-science.


  • Title: Breath
  • Author: James Nestor
  • Pages: 304
  • Format: EBook
  • Publisher: Riverhead books
  • ISBN: 0735213615
  • Genre: Pop-science