January 10, 2022 • 2hr 18min

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

Huberman Lab

In this episode, Dr. Andrew Huberman interviews Dr. Jack Feldman, a distinguished professor of neurobiology at UCLA and pioneering expert on the science of respiration. They discuss the neural control of breathing, how breathing influences mental and physical states, specific breathing protocols and their effects, and much more. Dr. Feldman provides a "master class" on breathing physiology and neuroscience, explaining complex concepts in an accessible way. He shares insights from decades of research on the brain circuits controlling respiration and how this knowledge can be applied to improve health and performance.

0:00

-0:00

Key Takeaways

The diaphragm is the primary muscle responsible for breathing. When it contracts, it pulls down and creates negative pressure in the lungs, causing air to flow in.
There are two main brain centers that control breathing rhythms:
- The pre-Bötzinger complex - controls inspiration/inhalation
- The parafacial nucleus - controls active expiration/exhalation
Physiological sighs occur about every 5 minutes and help re-inflate alveoli in the lungs that have collapsed. This is critical for maintaining lung function.
Breathing patterns can significantly impact brain states, emotions, and cognitive function. Slow, controlled breathing practices may help reduce fear/anxiety and improve focus.
Nasal breathing appears to have cognitive benefits over mouth breathing, likely due to increased activation of olfactory pathways to the brain.
Many physiological processes are coordinated with the breathing cycle, including heart rate, pupil dilation, fear responses, and reaction times.
Episodic hypoxia (intermittent low oxygen exposure) may have cognitive and motor performance benefits, though more research is needed.
Dr. Feldman recommends simple box breathing (e.g. 5 seconds inhale, hold, exhale, hold) as an accessible starting point for breath work. Even 5-10 minutes can be beneficial.
Magnesium L-threonate supplementation may help improve cognitive function by enhancing synaptic plasticity, though more studies are needed.

Introduction

In this episode, Dr. Andrew Huberman interviews Dr. Jack Feldman, a distinguished professor of neurobiology at UCLA and pioneering expert on the science of respiration. They discuss the neural control of breathing, how breathing influences mental and physical states, specific breathing protocols and their effects, and much more.

Dr. Feldman provides a "master class" on breathing physiology and neuroscience, explaining complex concepts in an accessible way. He shares insights from decades of research on the brain circuits controlling respiration and how this knowledge can be applied to improve health and performance.

Topics Discussed

Mechanics and Neural Control of Breathing (9:22)

Dr. Feldman explains the basic mechanics of breathing:

The diaphragm is the primary muscle for inhalation. When it contracts, it pulls down and expands the lungs.
At rest, exhalation is mostly passive - the lungs and ribcage relax back to their resting position.
Neurons in the brainstem control the rhythmic activation of respiratory muscles.

He describes his discovery of the pre-Bötzinger complex, a small region in the brainstem that generates the breathing rhythm:

Contains a few thousand neurons that initiate each breath
Activates motor neurons controlling the diaphragm and intercostal muscles

"Every breath begins with neurons in this region beginning to be active." - Dr. Jack Feldman

Physiological Sighs (34:55)

Dr. Feldman explains the importance of physiological sighs:

Occur about every 5 minutes automatically
Help re-inflate alveoli (air sacs) in the lungs that have collapsed
Critical for maintaining lung function and health
Triggered by neurons in the pre-Bötzinger complex responding to bombesin-related peptides

He describes experiments showing that eliminating sighs in rats led to deterioration of lung function and overall health.

Breathing and Brain States (59:52)

Dr. Feldman discusses the bidirectional relationship between breathing and brain/emotional states:

Stress and emotions can alter breathing patterns
Deliberately changing breathing patterns can shift mental/emotional states
Slow, controlled breathing may reduce fear/anxiety responses

He describes an experiment where mice trained to breathe slowly showed significantly reduced fear responses, comparable to major manipulations of the amygdala.

"The degree to which they showed less freezing was as much as if there was a major manipulation in the amygdala, which is a part of the brain that's important in fear processing. It's a staggering change." - Dr. Jack Feldman

Nasal vs. Mouth Breathing (39:41)

They discuss potential cognitive benefits of nasal breathing:

Studies show improved memory when learning information while nasal breathing vs mouth breathing
May be due to increased respiratory modulation of brain activity via olfactory pathways
More research needed to fully understand mechanisms and effects

Physiological Processes Coordinated with Breathing (43:20)

Dr. Feldman explains how many bodily functions are synchronized with the breathing cycle:

Heart rate varies with respiration (respiratory sinus arrhythmia)
Pupil size oscillates with breathing
Fear responses change between inspiration and expiration
Reaction times differ between inhalation and exhalation phases

"Almost everything. So we have, for example, on the autonomic side, we have respiratory sinus arrhythmia. That is, during expiration, the heart slows down, your pupils oscillate with the respiratory cycle." - Dr. Jack Feldman

Episodic Hypoxia (29:30)

They discuss potential benefits of intermittent low oxygen exposure:

May improve motor function and cognitive performance
Effects can persist for hours after exposure
Mechanism not fully understood, but differs from breath holding
More research needed on protocols and applications

Breath Work Practices (55:18)

Dr. Feldman shares his thoughts on breath work:

Recommends starting simple with box breathing (e.g. 5 second inhale, hold, exhale, hold)
Even 5-10 minutes can be beneficial
Different practices may work through different mechanisms
More controlled studies needed to optimize protocols

He describes his personal practice:

5-20 minutes of box breathing, often after lunch
Experimenting with other techniques like tummo breathing

"I find I get tremendous benefit by relatively short periods, between five and maybe 20 minutes of doing box breathing. It's very simple to do." - Dr. Jack Feldman

Magnesium L-Threonate and Cognitive Function (2:06:00)

Dr. Feldman discusses research on magnesium L-threonate supplementation:

May enhance synaptic plasticity and cognitive function
Crosses blood-brain barrier more effectively than other forms of magnesium
Human study showed cognitive improvements in those with mild cognitive impairment
More research needed, but promising for cognitive health

He shares his personal experience taking a half dose and seeing his blood magnesium levels increase from low-normal to high-normal.

Conclusion

This wide-ranging conversation provides a comprehensive overview of the neuroscience of breathing and its impacts on health and cognition. Dr. Feldman's pioneering work has revealed the intricate brain circuits controlling respiration and how they interact with other neural systems. This research opens up exciting possibilities for using targeted breathing practices to influence brain states, emotional regulation, and cognitive performance.

While more rigorous studies are still needed, the existing evidence suggests that even simple breathing exercises can have significant benefits. Dr. Feldman encourages people to experiment with practices like box breathing and to be open to the potential of breath work for improving mental and physical wellbeing.

The discussion also highlights promising areas for future research, including optimizing breath work protocols, understanding mechanisms of episodic hypoxia benefits, and exploring cognitive enhancement through supplements like magnesium L-threonate. Overall, this episode underscores the fundamental importance of breathing for brain function and offers practical insights for leveraging respiration to enhance health and performance.