Huberman LabBreathing for Mental & Physical Health & Performance | Dr. Jack Feldman
CHAPTERS
- 0:00 – 7:00
Intro, Guest Background, and Scope of Breathing Science
Huberman introduces Dr. Jack Feldman as the founder of modern breathing neuroscience and outlines the episode’s focus on how breathing impacts health, performance, and disease. They frame breathing as not just a metabolic necessity but a powerful regulator of mental states and organ function, and preview that Feldman will share both mechanisms and practical protocols.
- •Feldman is a distinguished UCLA neurobiologist known for discovering core brain centers controlling breathing.
- •Breathing variables—rate, depth, inhale/exhale ratio—predict focus, sleep onset, and transitions between arousal states.
- •Neural control of breathing was poorly understood before Feldman’s work, despite breathing being essential for life.
- •The episode aims to connect fundamental mechanisms (brainstem circuits) with practical breathwork applications.
- 7:00 – 22:00
Sponsors and Resource: Nootropics, Foundational Nutrition, and Breathwork Collective
Huberman briefly describes three sponsors—Thesis nootropics, Athletic Greens, and Headspace—and introduces Our Breath Collective as an optional paid resource for deeper breathwork training. He emphasizes the podcast’s mission to provide free, science-based tools while acknowledging the value of structured programs developed with experts like Feldman.
- •Thesis offers targeted nootropic blends for specific cognitive states, highlighting individual variability in response.
- •Athletic Greens is presented as a comprehensive micronutrient and probiotic foundation with added vitamin D3/K2.
- •Headspace provides structured meditation content of varying lengths, aiding adherence to meditation practice.
- •Our Breath Collective offers live guided sessions and courses on breathwork; Feldman is an advisor (Huberman is not), and listeners can get a discount via Huberman’s link.
- 22:00 – 35:00
Fundamentals: Mechanics and Muscles of Breathing
Feldman explains how inhalation and exhalation work mechanically, centering on the diaphragm and intercostal muscles. He differentiates skeletal muscles (which require neural drive) from smooth muscles in the airways and touches on conditions like asthma, emphasizing that core breathing muscles are under neural control and that expiration at rest is passive.
- •Inhalation expands lung volume, lowering alveolar pressure so air flows in; exhalation at rest is passive recoil.
- •The diaphragm (skeletal muscle) is the primary inspiratory muscle, assisted by external intercostals lifting the ribs.
- •Smooth muscles in airways can constrict inappropriately in asthma, impairing airflow; this is separate from brainstem rhythm generation.
- •Diaphragm and intercostal activation is largely agnostic to nose vs mouth breathing at the level of spinal motor neurons.
- •Asthma is likely not caused directly by preBötzinger or rhythm centers, though this isn’t fully ruled out.
- 35:00 – 48:00
Discovery of the PreBötzinger Complex and a Second Breathing Oscillator
Feldman recounts identifying the preBötzinger complex as the core inspiratory rhythm generator and later realizing there must be a separate expiratory oscillator. He clarifies the concept of neural oscillators, explains why passive expiration initially obscured the second oscillator, and describes the parafacial/retrotrapezoid region’s role in active expiration and CO₂ sensing.
- •The preBötzinger complex, located bilaterally in the brainstem, initiates each inspiratory burst that drives diaphragm and intercostal motor neurons.
- •Expiration at rest is passive, so active expiratory circuits are silent and were initially missed.
- •A second oscillator near the facial nucleus (retrotrapezoid/parafacial) generates active expiration during forced breathing, exercise, and gasping.
- •This region is also involved in central chemoreception—sensing CO₂ and thus pH to protect brain function.
- •Breathing oscillators evolved alongside facial motor systems; in non-mammals, active expiration and passive inspiration are the norm.
- 48:00 – 59:00
Evolutionary Advantage of the Diaphragm and Massive Lung Surface Area
Feldman explores the evolutionary development and mechanical efficiency of the diaphragm, showing how it allows mammals to pack enormous gas-exchange surface area into a small chest. He connects diaphragm evolution to the energy demands of large brains and contrasts mammalian lungs with those of amphibians and reptiles.
- •Human lungs contain ~4–500 million alveoli with a total surface area of ~70 m² (about a third of a tennis court).
- •The diaphragm’s position and mechanics allow a small downward movement (~2/3 inch) to stretch this huge membrane by ~20% lung volume, sufficing for normal metabolism.
- •Amphibians and reptiles lack a diaphragm and rely on active expiration/passive inspiration with much less alveolar branching and gas-exchange surface.
- •High, continuous oxygen demands of large mammalian brains likely depended on diaphragm evolution.
- •Breathing control must adapt as the body grows and ribcage stiffens, akin to “building an airplane while it’s flying.”
- 59:00 – 1:12:00
Diaphragmatic vs ‘Chest’ Breathing and Early Thoughts on Breath Practices
Huberman asks about the popular emphasis on ‘diaphragmatic breathing’ and whether belly vs chest movement matters. Feldman notes we are obligate diaphragm breathers under normal conditions and is agnostic about many stylistic distinctions in current breathwork, suggesting emotional/cognitive effects likely arise from broader neural and gas-exchange mechanisms.
- •At baseline, humans are fundamentally diaphragm breathers; other muscles can compensate if the diaphragm is impaired, but with limits on increased ventilation.
- •Visible belly vs chest motion reflects different muscle recruitment but may not be the primary determinant of cognitive/emotional effects.
- •Feldman is more interested in mechanisms like blood gases, neural oscillations, and afferent feedback than in precise abdominal vs thoracic emphasis.
- •He sees many modern breathwork claims as under-tested and calls for more rigorous mechanistic studies.
- 1:12:00 – 1:31:00
Physiological Sighs: Why You Sigh Every Five Minutes
Feldman gives a detailed account of physiological sighs—large, often unnoticed breaths occurring every few minutes in humans and more frequently in smaller animals. He explains how fluid-lined alveoli tend to collapse due to surface tension, how sighs reopen them, and how both clinical ventilator practices and targeted brainstem experiments highlight sighs’ life-sustaining role.
- •Alveoli are tiny, fluid-lined sacs prone to collapse from surface tension; collapsed alveoli cannot participate in gas exchange.
- •Normal tidal breaths can’t reliably reopen collapsed units; intermittent deeper breaths (sighs) are needed to ‘pop’ them open.
- •Humans sigh spontaneously about every five minutes; rats, being smaller, sigh more often (~every two minutes).
- •Historical iron-lung treatment for polio showed that adding periodic large breaths (mimicking sighs) dramatically reduced mortality.
- •Modern ventilators deliberately include periodic “super breaths” to prevent alveolar collapse.
- •Feldman’s lab showed bombesin-related peptides in the preBötzinger complex can drive sigh frequency from ~20–30/hour to ~500/hour in rats, and selective ablation of peptide-sensitive neurons nearly abolishes sighs, leading to deteriorating breathing and likely lung damage.
- 1:31:00 – 1:40:00
Sighs, Gasps, and Death: Speculations on Overdose and Neurodegeneration
They discuss whether impaired sighing or gasping might contribute to deaths from drug overdose or neurodegenerative diseases. Feldman notes that many mammals show slowing breathing then gasping near death and posits gasps as an autoresuscitation attempt that might fail if certain brainstem circuits are compromised, as in Parkinson’s, MSA, or ALS.
- •Near-death patterns often include apnea followed by large gasps (“dying gasp”), potentially an attempt at self-resuscitation.
- •If gasping or sigh circuits are suppressed (by drugs or neurodegeneration), the chance of spontaneous recovery from respiratory failure could be reduced.
- •Post-mortem data indicate neuron loss in preBötzinger in disorders like Parkinson’s, MSA, and possibly ALS; Feldman hypothesizes they may die during sleep from unrescued apnea.
- •These ideas remain speculative but highlight the importance of brainstem breathing networks in sudden death.
- 1:40:00 – 1:57:00
Bombesin, Peptides, and the Discovery of Sigh-Specific Neurons
Feldman narrates the serendipitous discovery that stress-related bombesin peptides strongly drive sighing. He explains the clever use of saporin-conjugated peptides to selectively kill only those neurons expressing specific receptors in the preBötzinger complex, confirming their role in sigh generation, and then recounts how this intersected with Marc Krasnow’s lab via a memorable ‘prisoner’s dilemma’ interaction.
- •Stress triggers hypothalamic release of bombesin-related peptides; stress also increases sighing, suggesting a link.
- •Direct microinjection of bombesin into rat preBötzinger complex caused a massive increase in sigh rate (~20–30/hour to ~500/hour).
- •Using bombesin conjugated to saporin, Feldman’s lab selectively ablated bombesin-receptor-expressing neurons, leading to progressive loss of sighs and deteriorating breathing.
- •Magnetic anecdote: Feldman and Krasnow’s labs independently converged on bombesin-related peptides in breathing circuits; a playful information exchange led to collaboration, not competition.
- 1:57:00 – 2:11:00
Breath, Meditation, and Teaching Mice to ‘Meditate’
Inspired by reading about mindfulness, Feldman took a meditation course to test whether breathing specifically mattered. Concluding that it did, he sought to model ‘meditation’ in rodents via controlled breathing, eventually developing a protocol that slowed mice’s breathing dramatically. Chronic slow breathing produced robust reductions in fear responses, strongly suggesting a non-placebo, mechanistic effect.
- •Feldman, new to mindfulness, suspected breath control was a causal ingredient rather than mere attentional anchor.
- •He received an NCCIH grant to explore breath-related interventions in rodents, aiming to isolate breathing from subjective factors.
- •After years of trial and error, his team found a way to slow awake mice’s breathing by a factor of ~10 for 30 minutes/day over 4 weeks.
- •In fear-conditioning tests, slow-breathing mice showed markedly less freezing versus controls—magnitude comparable to amygdala circuit manipulations.
- •Rodent models circumvent human placebo effects and support the idea that breath practice directly alters fear circuitry.
- 2:11:00 – 2:26:00
Bidirectionality: How Emotion Controls Breathing and Vice Versa
The conversation shifts to the mutual influence of breathing and emotion. Feldman reviews classic findings that amygdala stimulation alters breathing patterns and describes locked-in syndrome cases where voluntary breathing control is lost but emotion-driven breathing (e.g., laughter) persists. He then digs into Yakel’s work showing direct inspiratory projections to locus coeruleus that modulate arousal and calmness.
- •Amygdala stimulation in animals can evoke diverse, powerful breathing patterns, showing strong descending emotional control.
- •Locked-in syndrome patients cannot voluntarily alter breathing yet still show breathing changes when they laugh at jokes, implying separate emotional pathways.
- •Facial muscles and breathing both have dual control systems: volitional and emotional, often anatomically separable.
- •Yakel et al. identified preBötzinger neurons that project to locus coeruleus; ablating these cells made animals calmer and altered EEG signatures.
- •Breathing-related input to locus coeruleus likely links respiratory rhythm to global arousal and attention states.
- 2:26:00 – 2:38:00
Multiple Pathways: Nose, Vagus, CO₂, and Cortical Oscillations
Feldman maps out several routes by which breathing modulates brain function: nasal airflow into olfactory circuits, mechanosensory and visceral signals via the vagus nerve, changes in CO₂/pH, and top-down motor commands during volitional breathwork. He argues that these converge to create respiratory oscillations in cortex, timing or gating information processing across the brain.
- •Nasal breathing drives rhythmic input from the nasal mucosa to the olfactory bulb, which projects broadly to limbic and cortical areas.
- •The vagus nerve carries strongly respiratory-modulated afferent signals from lung stretch receptors and other viscera into the brainstem.
- •Vagus nerve stimulation is a recognized treatment for refractory depression, indicating that vagal signals can meaningfully shape mood.
- •CO₂ fluctuations alter pH and strongly drive breathing; chronically low or high CO₂ can influence anxiety and panic.
- •Volitional breathing engages motor cortex and associated pathways, sending ‘corollary’ signals to other brain regions that may modulate emotion and cognition.
- •Breathing-related oscillations in cortex likely help synchronize disparate sensory streams and could be repurposed by deliberate breathing patterns.
- 2:38:00 – 2:53:00
Breath Holds, Cyclic Hyperventilation, and Episodic Hypoxia
Huberman raises Wim Hof/Tummo-style breathing (cyclic hyperventilation plus breath holds) and asks how it compares to lab-defined episodic hypoxia. Feldman distinguishes their gas profiles—CO₂ and O₂ trajectories differ—and introduces work on episodic hypoxia as a tool for long-lasting enhancements in breathing drive, motor performance, and possibly cognition.
- •Breath holds simultaneously lower oxygen and raise CO₂, whereas episodic hypoxia in research typically uses low-oxygen gas with more stable CO₂.
- •Episodic hypoxia (e.g., 3 minutes low O₂, 5 minutes normoxia, repeated) can lead to prolonged increases in ventilation and improved motor outputs.
- •Clinical data show stroke patients can exhibit significantly stronger ankle extension after episodic hypoxia bouts.
- •Feldman speculates on applications for spinal rehab and motor sports; jokingly mentions golf as a testbed because of its motor and cognitive demands.
- •He cautions that Tummo/Wim Hof breathing approximates some aspects of episodic hypoxia but likely does not match the depth of hypoxia used in controlled studies.
- 2:53:00 – 3:05:00
Nasal vs Mouth Breathing, Unilateral Nostrils, and Respiratory Modulation of Behavior
They revisit nasal breathing, including evidence that it enhances certain memory functions via olfactory-hippocampal coupling. Feldman notes that even with blocked nasal airflow, central respiratory signals still modulate olfactory bulb activity. They also touch on lateralization and the possibility (still largely anecdotal) that right vs left nostril breathing might differentially affect brain hemispheres.
- •Journal of Neuroscience studies showed nasal breathing during learning improved olfactory and hippocampal-dependent memory versus mouth breathing.
- •Nasal airflow creates strong respiratory signals in the olfactory bulb; however, there are also central respiratory inputs to the bulb regardless of airflow.
- •The brain is highly lateralized; in principle, asymmetric olfactory inputs from one nostril could bias hemispheric activity differently.
- •Direct mechanistic evidence for distinct right- vs left-nostril cognitive/emotional effects in humans is limited; Feldman views current claims as plausible but unproven.
- 3:05:00 – 3:18:00
Breathing’s Ubiquitous Footprint: Reaction Time, Fear Perception, and Martial Arts
Feldman argues that breathing’s influence extends to nearly all brain and body functions. He cites studies showing respiratory-phase-dependent changes in fear processing, reaction time, and motor output. They briefly speculate about martial artists potentially exploiting such timing and reiterate that many cortical phenomena might be driven by underlying respiratory rhythms.
- •Fear responses to stimuli (e.g., fearful faces) differ between inspiration and expiration, implicating respiratory phase in emotional perception.
- •Reaction times and movement initiation (e.g., a punch) vary with the respiratory cycle.
- •Heart rate, pupil size, and other autonomic variables show strong respiratory coupling (e.g., respiratory sinus arrhythmia).
- •Many brain imaging findings attributed to specific movements might actually be driven by co-occurring breathing changes.
- •Breathing provides a slow but globally synchronized oscillation that could frame how the brain integrates information.
- 3:18:00 – 3:30:00
Breathwork as Controlled Disruption of Maladaptive Brain Circuits
Feldman develops a conceptual model of breathwork: changing breathing patterns disrupts ongoing oscillatory circuits in the brain, which may weaken entrenched pathological loops (e.g., in depression) in a way analogous to, but gentler than, ECT or deep brain stimulation. He likens pathological circuits to deep ruts and breath practice to gradually filling those ruts so the system can escape.
- •Neural oscillations organize information processing; breathing is a uniquely adjustable, slow oscillator that pervades brain networks.
- •Persistent pathological loops (e.g., in depression) may depend on stable timing relationships; disrupting these can weaken the circuits.
- •Breath practices produce extended, structured perturbations of respiratory-linked oscillations, potentially reshaping network dynamics.
- •This framework can explain why different practices (slow breathing vs hyperventilation + holds) produce different subjective and clinical effects.
- •Feldman calls for systematic mechanistic research to identify optimal frequencies, patterns, and durations for various conditions.
- 3:30:00 – 3:43:00
Practical Breathwork: Feldman’s Own Protocols and ‘Box Breathing’
Huberman asks what Feldman actually does with all this knowledge in his own life. Feldman emphasizes simplicity and accessibility, likening breath training to starting exercise after being sedentary. He uses short, daily box-breathing sessions (e.g., 5–20 minutes, 5-second per phase) and occasionally adjusts durations, describing clear benefits for calmness and midday reset.
- •Feldman is a relatively new breathwork practitioner and favors straightforward protocols that are easy to adopt.
- •His go-to practice is box breathing: ~5s inhale, 5s hold, 5s exhale, 5s hold, repeated for 5–20 minutes, sometimes lengthened to 10s phases.
- •He often uses a simple app to keep timing and sometimes inserts breath sessions after lunch to combat performance dips.
- •He is exploring more intense methods like Tummo/Wim Hof but remains cautious about mechanistic claims.
- •For newcomers, he recommends experimenting with short (5–10 minute) daily sessions and noticing personal benefit before escalating complexity or duration.
- 3:43:00 – 3:53:00
Pattern Variability, Transitions, and the Need for Better Human Studies
They discuss the idea that experiencing transitions across different breathing patterns (e.g., changing box dimensions, switching to other styles) might itself be powerful, giving the brain multiple perturbations to adapt to. Feldman notes the lack of systematic work comparing patterns and emphasizes the importance of animal models to dissect mechanisms and guide human trials.
- •Transitioning among breathing styles may engage distinct neural and physiological pathways (nasal vs vagal vs CO₂ vs cortical command).
- •No comprehensive dataset yet compares multiple breath patterns across standardized outcomes in humans.
- •Rodent models are crucial to map specific pathways and to identify resonant frequencies/patterns that maximize beneficial effects.
- •Feldman urges more serious neuroscientists and psychologists to invest in careful, mechanistic breathwork studies.
- 3:53:00 – 4:12:00
Magnesium Threonate, Synaptic Noise, and Cognitive Aging
Feldman pivots to supplements, specifically magnesium threonate, disclosing his scientific advisory role to Neurocentria. He recounts Guosong Liu’s work showing that modestly raising extracellular magnesium reduces synaptic noise and enhances LTP, then describes rodent and human data suggesting magnesium threonate improves learning, memory, and age-related cognitive decline.
- •Early in vitro work showed that raising extracellular magnesium within physiological range reduced baseline synaptic noise and increased LTP in hippocampal neurons.
- •Standard magnesium salts poorly cross the gut–blood–brain barriers; high doses cause diarrhea.
- •Magnesium threonate, leveraging threonate (a vitamin C metabolite) transport systems, more efficiently elevates brain magnesium.
- •Rodent studies: magnesium threonate-enhanced diets improved cognitive performance and lifespan metrics.
- •In a double-blind human trial with mild cognitive impairment, average cognitive age improved by ~8 years in the magnesium threonate group versus ~2 years in placebo, pulling participants closer to their biological age.
- •Feldman himself takes about half the commercial dose, titrated to keep blood magnesium in high-normal range; he notes colleagues often report better sleep on it.
- 4:12:00
Closing Reflections: The Future of Breathing Neuroscience and Public Education
Huberman thanks Feldman for his foundational work in breathing neuroscience and for sharing both mechanistic insights and practical tools. Feldman expresses appreciation for the opportunity to reach beyond his academic silo and reiterates his belief that understanding and leveraging breathing has enormous potential for improving human health and performance.
- •Huberman underscores that Feldman’s decades of work laid the groundwork for today’s surge of interest in breathwork and respiratory health.
- •Feldman values public engagement and is struck by how willing lay audiences are to grapple with sophisticated mechanisms.
- •They agree that breathing remains underexplored relative to its brain-wide impact and potential therapeutic leverage.
- •The episode closes with references to support channels (sponsors, Patreon, Thorne partnership) and another mention of Our Breath Collective for structured breath training.
