This episode my guest is Dr. Jack Feldman, Distinguished Professor of Neurobiology at the University of California, Los Angeles and a pioneering world expert in the science of respiration (breathing). We discuss how and why humans breathe the way we do, the function of the diaphragm and how it serves to increase oxygenation of the brain and body. We discuss how breathing influences mental state, fear, memory, reaction time, and more. And we discuss specific breathing protocols such as box-breathing, cyclic hyperventilation (similar to Wim Hof breathing), nasal versus mouth breathing, unilateral breathing, and how these each affect the brain and body. We discuss physiological sighs, peptides expressed by specific neurons controlling breathing, and magnesium compounds that can improve cognitive ability and how they work. This conversation serves as a sort of "Master Class" on the science of breathing and breathing-related tools for health and performance.  For the full show notes, visit hubermanlab.com. Thank you to our sponsors AG1 (Athletic Greens): https://athleticgreens.com/huberman LMNT: https://drinklmnt.com/huberman Thesis: https://takethesis.com/huberman Supplements from Momentous https://www.livemomentous.com/huberman Our Breath Collective https://www.ourbreathcollective.com/huberman  Timestamps (00:00:00) Introducing Dr. Jack Feldman (00:03:20) Sponsors: AG1, LMNT, Thesis, Momentous (00:10:35) Why We Breathe  (00:14:35) Neural Control of Breathing: “Pre-Botzinger Complex” (00:16:20) Nose vs Mouth Breathing (00:18:18) Skeletal vs. Smooth Muscles: Diaphragm, Intracostals & Airway Muscles (00:20:11) Two Breathing Oscillators: Pre-Botzinger Complex & Parafacial Nucleus (00:26:20) How We Breathe Is Special (Compared to Non-Mammals) (00:33:40) Stomach & Chest Movements During Breathing (00:36:23) Physiological Sighs, Alveoli Re-Filling, Bombesin (00:49:39) If We Don’t Sigh, Our Lung (& General) Health Suffers (01:00:42) Breathing, Brain States & Emotions  (01:05:34) Meditating Mice, Eliminating Fear  (01:11:00) Brain States, Amygdala, Locked-In Syndrome, Laughing (01:16:25) Facial Expressions (01:19:00) Locus Coeruleus & Alertness (01:29:40) Breath Holds, Apnea, Episodic Hypoxia, Hypercapnia (01:35:22) Stroke, Muscle Strength, TBI (01:38:08) Cyclic Hyperventilation (01:39:50) Hyperbaric Chambers (01:40:41) Nasal Breathing, Memory, Right vs. Left Nostril (01:44:50) Breathing Coordinates Everything: Reaction Time, Fear, etc. (01:57:13) Dr. Feldman’s Breathwork Protocols, Post-Lunch  (02:02:05) Deliberately Variable Breathwork: The Feldman Protocol (02:06:29) Magnesium Threonate & Cognition & Memory  (02:18:27) Gratitude for Dr. Feldman’s Highly Impactful Work (02:20:53) Zero-Cost Support, Sponsors, Instagram, Twitter, Supplements Title Card Photo Credit: Mike Blabac Disclaimer