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Essentials: Breathing for Mental & Physical Health & Performance | Dr. Jack Feldman

November 13, 2025 • 49m

Summary

⏱️ 8 min read

Overview

Dr. Jack Feldman, a leading neuroscientist specializing in respiration, discusses the fundamental mechanisms of breathing, the pre-Bötzinger complex discovery, and the profound connections between breath and brain function. He covers physiological sighs, breathing practices backed by rodent studies showing reduced fear responses, and the cognitive benefits of magnesium threonate supplementation. The conversation bridges basic neuroscience with practical applications for mental health, cognitive enhancement, and longevity.

Mechanics of Breathing and the Diaphragm

Feldman explains the fundamental mechanics of respiration, emphasizing the diaphragm's critical role in expanding the lungs and creating airflow. He discusses how the pre-Bötzinger complex in the brainstem initiates each breath by activating motor neurons controlling the diaphragm and intercostal muscles. The conversation highlights how mammals' evolutionary advantage stems from having a diaphragm, which allows for efficient oxygen exchange across approximately 500 million alveoli, equivalent to a membrane the size of a third of a tennis court.

  • Breathing serves to bring oxygen in and remove carbon dioxide, which is critical for maintaining blood pH balance
  • The diaphragm is the principal muscle of breathing, contracting downward to expand the thoracic cavity and create negative pressure that draws air in
  • The pre-Bötzinger complex, containing a few thousand neurons on each side of the brainstem, initiates every breath
  • At rest, nasal breathing is preferred, but during exercise, mouth breathing allows for greater airflow through larger airways

Evolutionary Advantage of the Diaphragm

Feldman provides fascinating evolutionary context for why mammals developed the diaphragm and how it enabled larger brain development. Unlike amphibians and reptiles that breathe by actively expiring and passively inspiring, mammals breathe the opposite way due to the mechanically efficient diaphragm. This efficiency allows mammals to pack extraordinary surface area into their lungs—approximately 500 million alveoli—enabling sufficient oxygen delivery to support energy-demanding organs like the brain.

  • Mammals are unique among vertebrates in having a diaphragm; amphibians and reptiles breathe by actively expiring rather than inspiring
  • The diaphragm's mechanical efficiency allows expansion of a 70 square meter membrane (500 million alveoli) by moving just two-thirds of an inch
  • During normal breathing, the diaphragm moves about half a liter of air (the size of a fist), increasing lung volume by 20%
" I would say a key step in the ability to develop a large brain that has a continuous demand for oxygen is the diaphragm. Without a diaphragm, you're an amphibian. "

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