There is nothing more essential to our health and wellbeing than breathing: take air in, let it out, repeat 25,000 times a day. Yet, as a species, humans have lost the ability to breathe correctly, with grave consequences. Journalist James Nestor travels the world to figure out what went wrong and how to fix it.

Here is an extract focusing on mouthbreathing from his book Breath, published by Penguin Random House.

Mouthbreathing, it turns out, changes the physical body and trans- forms airways, all for the worse. Inhaling air through the mouth de- creases pressure, which causes the soft tissues in the back of the mouth to become loose and flex inward, creating less overall space and making breathing more difficult. Mouthbreathing begets more mouthbreathing. 

Inhaling from the nose has the opposite effect. It forces air against all those flabby tissues at the back of the throat, making the airways wider and breathing easier. After a while, these tissues and muscles get “toned” to stay in this opened and wide position. Nasal breathing begets more nasal breathing. 

“Whatever happens to the nose affects what’s happening in the mouth, the airways, the lungs,” said Patrick McKeown during a phone interview. He’s a bestselling Irish author and one of the world’s leading experts on nasal breathing. “These aren’t separate things that operate autonomously— it’s one united airway,” he told me. 

None of this should come as a surprise. When seasonal allergies hit, incidences of sleep apnea and breathing difficulties shoot up. The nose gets stuffed, we start mouthbreathing, and the airways collapse. “It’s sim- ple physics,” McKeown told me. 

Sleeping with an open mouth exacerbates these problems. Whenever we put our heads on a pillow, gravity pulls the soft tissues in the throat and tongue down, closing off the airway even more. After a while, our airways get conditioned to this position; snoring and sleep apnea be- come the new normal. 

The Carousel would like to thank Penguin Random House for this extract of James Nestor’s book Breath.

This is an extract from Breath by James Nestor, published by Penguin Random House, $35. Available to purchase now.