The Gravity Doctors

In this reflective "backyard" session in Los Angeles, Brennan and his co-host discuss the current state of BiogravitationalMedicine (BGM) and the Mental Gravity theory. They explore the challenges of introducing a physics-based framework into the traditional silos of medicine and psychology, the excitement of early adopters, and how a simple shift in perspective—viewing the body as a "physics-fighting engine"—can empower individuals to take control of their health.Key Takeaways:Physics First, Biology Second: The core of BGM is the understanding that our minds and bodies are a directconsequence of evolving under Earth's gravity.The Hub of the Wheel: Gravity is presented not as a new "spoke" of medicine, but as the hub that connects all physiological systems and illnesses.Mental Gravity as a Practice: The "Mental Gravity" app translates these theories into pragmatic, intuitive steps for mental fitness, moving away from abstract psychologicalterms toward grounded physical principles.Breaking the Silos: Despite pushback from specialists who prefer to stay in their "lanes," BGM seeks to bridge the gap between physics, gastroenterology, neuroscience, and psychology.The "Space Science" Connection: The ill effects astronauts experience from a lack of gravity serve as a powerful "AHA!" moment for skeptics to understand why gravity is essential for terrestrial health.Timestamps:00:00 – Reflective Mood in LA: Assessing the progress of Biogravitational Medicine one to two years in. 01:30 – Understanding the Framework: Why people resonate with the idea that life emerged to manage physics. 03:00 – Mental Gravity & Intuitive Health: Launching the Mental Gravity company and app to describe feelings in grounded, physical terms. 04:00 – Mainstream Endorsement: Discussing the deep-dive conversation with Mel Robbins and the pragmatic side of BGM. 06:00 – Closing the Knowledge-Action Gap: Empowering individuals to correct their perception of "mental weight" through action. 07:30 – Aristotle vs. Plato: Moving from the "Platonic realm" of abstract ideals back down to the grounded "Aristotelian" reality of the body. 09:30 – Language vs. Reality: Why "feeling down" is more than just a metaphor—it’s a physical consequence. 12:00 – "Off the Deep End": Dealing with skepticism and the stigma of mixing physics with clinical medicine. 15:30 – Universal Principles: Drawing parallels between BGM and models used in economics and chaos theory. 17:00 – The Free Energy Principle: How neuroscience is already beginning to use physics-based tools like active inference. 19:30 – The Space Medicine Niche: How the peer-review process is opening up through the lens of astronaut health. 21:00 – Interrelated Systems: Lessons from gastroenterology on how the brain, gut, and microbiome are all physically connected. 23:30 – The Goldilocks Zone: Achieving balance between sedentary living and overtraining within 1G of force. 25:30 – The "Let Them" Mindset Shift: Why BGM is a powerful psychological tool for health promotion. 26:45 – Wrapping Up: A look toward the next year of evolution for the theory.ResourcesThe Gravity Doctors: ⁠https://thegravitydoctors.com⁠ Dr. Brennan Spiegel: ⁠https://brennanspiegelmd.com⁠ Dr. Lachlan Kent: ⁠https://lachlankent.au⁠ Book — Pull: How Gravity Shapes Your Body, Steadies the Mind, and Guides Our Health

In this episode, Dr. Brennan Spiegel (physician, gastroenterologist, and author of Pull) and Dr. Lachlan Kent(cognitive scientist and founder of Mental Gravity) explore the physical, psychological, and existential implications of humanity's return to the moon.They examine how the Artemis mission acts as a "Global Unifier," shifting the narrative from territorial conflict to a collective human achievement.Broadcasting as a "crew of two," they reflect on the transition from the stoic, emotionally restrained era of Apollo to the joyful, diverse, and deeply "human" experience of modern space exploration. They connect the physics of "untethering"from Earth to the metaphysics of "mental gravity," arguing that space travel is the ultimate expression of humanity's anti-gravity mission. One Giant Leap for Humanity: The ArtemisPerspectiveA Global Unifier: A 21st-century mission that transcends national borders, bringing the world together to witness one of humanity's greatest achievements.The Physics of Fragility: An exploration of the "immense forces" required to fight gravity and the vulnerability of the human body in zero-G environments.The Overview Effect: The profound psychological realization that occurs when astronauts look back at the planet and see it not as a collection of countries, but as a single "crew" on Spaceship Earth.Humanizing Space: A shift from the "stoic" pilots of the 1960s to a mission characterized by visible joy, big hugs, and diverseleadership.Space Travel as a Biogravitational MissionBreaking the Tether: Humanity’s evolutionary history is defined by standing up and using intelligence to build machines that allow us to fly and eventually "blast off" from the planet.The Two Portals: Space travel forces a confrontation with two realities: the "awe-inspiring" view of home and the "existential dread" of the black void.Inner Space vs. Outer Space: The lessons learned from reaching the moon are applied to "inner space," helping individuals navigate the gravitational pull of their own minds.Timecodes00:04 — Introduction to the Artemis mission and its global significance.00:30 — Exploring the social and spiritual implications of overcoming gravity.01:38 — Artemis as a "Global Unifier"transcending national borders.02:14 — The physics of untethering and the fragility of the human body.02:43 — Reflections on looking back at "SpaceshipEarth".04:24 — Humanizing space: Comparing modern joy and diversity to Apollo-era stoicism.05:56 — The nuance of falling and fighting gravity as alife force.07:34 — Standing up as humanity's existential mission.08:41 — The anti-gravity mission: Breaking the tether to bring consciousness beyond Earth.10:11 — Space travel as a driver for new scientific and experiential understanding.12:37 — Pioneering, science, and the phenomenology of the unknown.14:56 — Mental Gravity: Elevation and perspective vs.the "stuckness" of depression.16:11 — The Astronaut's Perspective: De-centering tofind meaning and universal connection.18:43 — The Two Portals: Navigating the "OverviewEffect" (awe) and the black void (dread).22:16 — The spiritual dimension of gravity and the physical induction of awe.22:39 — Oceanic consciousness, ego dissolution, and the transient self.25:26 — Choosing a portal: Naturalistic spirituality and the news of a "cosmic whole".27:00 — The evolution of the "crew":Interconnection as a strategy for mutual survival.28:42 — Selflessness vs. Selfishness: Finding hopeful signs of social cohesion.32:00 — Convergence: Biogravitational medicine as a holistic approach to humanity's future.34:56 — Closing: Inviting others into the"crew" and future launch of Mental Gravity.ResourcesThe Gravity Doctors: https://thegravitydoctors.com Dr. Brennan Spiegel: https://brennanspiegelmd.com Dr. Lachlan Kent: https://lachlankent.au Book — Pull: How Gravity Shapes Your Body, Steadies the Mind, and Guides Our Health

Dr Brennan Spiegel (physician, gastroenterologist, and author of Pull) and Dr Lachlan Kent (cognitive scientist and founder of Mental Gravity) explore how seasons, sunlight, serotonin, and gravity shape mood, attraction, and human connection.Broadcasting from opposite hemispheres—Brennan in winter in Los Angeles and Lachlan in summer in Melbourne—they examine why people often feel more “down” in winter, why this is linked to reduced sunlight and serotonin, and how this helps explain the phenomenon known as “cuffing season”—the seasonal urge to pair up.They connect dating, love, posture, breath, yoga, serotonin, oxytocin, and even planetary orbits into a single biogravitational story: human connection is shaped by the same gravitational cycles that shape the seasons themselves.Seasons as Gravitational CyclesSeasons arise from Earth’s orbit around the sunNot just temperature cycles, but gravitational and light cyclesMood follows seasonal gravity:Summer = outward, expansive, lightWinter = inward, heavy, contractingBreath mirrors this cycle: in/up, out/downWinter, Serotonin, and Mental GravitySunlight boosts serotoninLow winter sunlight → lower serotonin → heavier moodSeasonal Affective Disorder (SAD) as a gravity-related mood stateSerotonin as a “gravity management molecule” that supports:Muscle toneCirculationUpright postureMental elevationLove, Attraction, and Gravity“Falling in love” uses gravitational language Uprightness—physical, emotional, moral—is attractiveWinter dating favors depth over displaySpring favors peacocking; winter favors bondingLong-term connection as gravitational alignment of valuesWinter Practices for Gravity ResilienceMovement & PostureYoga as a winter-friendly anti-gravity practiceInversions, posture, alignment, balanceLow-intensity movement over intense trainingLight &EnvironmentMaximize sunlight exposureUse light boxes in high-latitude wintersGet outside when possibleDiet & ChemistryTryptophan-rich foods: turkey, avocado, chicken, chickpeas, kidney, beans, eggs, tofu, nutsSupport serotonin production through dietConnectionCuddling, closeness, bondingOxytocin releaseOxytocin → vagus nerve → serotoninParasympathetic “rest and digest” stateNeurochemistry of Winter BondingOxytocin primes vagus nerveVagus nerve regulates serotonin releaseCuddling + calm = anti-gravity physiologyParasympathetic tone matches seasonal slowingBiogravitational Medicine in Daily LifeHuman health reflects planetary physicsSun, moon, Earth, and orbit shape biologyMood, love, and seasons are not mystical—just naturalGravity as the hidden organizer of emotion, posture, and connectionTimecodes00:00 — Welcome & hemispheres01:15 — Seasons and gravity02:15 — What is cuffing season?03:15 — Mood, winter, and seasonal affect04:40 — Sunlight, serotonin, and heaviness06:05 — Planetary cycles and breath cycles07:15 — Love as anti-gravity08:15 — Depth vs display in dating09:20 — Uprightness and attraction10:45 — Winter activities and posture11:35 — Yoga and winter gravity13:15 — Balance, breath, and alignment15:40 — Light therapy and sunlight16:40 — Diet and serotonin foods16:55 — Cuddling, oxytocin, vagus nerve18:15 — Parasympathetic winter mode19:05 — Biogravitation and planetary life20:35 — Falling in love & falling physically21:00 — Closing reflectionsResourcesThe Gravity Doctors: https://thegravitydoctors.comDr Brennan Spiegel: https://brennanspiegelmd.comDr Lachlan Kent: https://lachlankent.auBook — Pull: How Gravity Shapes Your Body, Steadies the Mind, and Guides Our Health

Dr Brennan Spiegel (physician, gastroenterologist, and author of Pull) and Dr Lachlan Kent (cognitive scientist and founder of Mental Gravity) drop an emergency episode to unpack one of the most extreme acts of gravity defiance ever witnessed: Alex Honnold climbing a 100-plus-storey skyscraper without ropes.Using Honnold as an “extreme phenotype,” they explore what his remarkable calm reveals about fear, anxiety, graviception, and mental gravity. Drawing on neuroscience, psychology, and lived experience, they examine how Honnold’s quiet amygdala, finely tuned salience network, and relentless present-momentfocus allow him to operate where most humans would be paralysed by fear.The episode bridges elite performance and everyday mental health, asking: what can the rest of us learn—safely—from someone who literally does not fear falling?1. Why Alex Honnold MattersA real-world example of ultimate gravity resilienceFree-solo climbing as the most literal test of mental gravityAnxiety, fear of falling, and bodily panic stripped awayA window into the far edge of human psychological capacityFear, Falling, and the Brain AmygdalaHonnold’s amygdala shows minimal activation to fear-inducing stimuliContrast with anxiety, chronic pain, IBS, and fibromyalgia, where the amygdala is hyper-vigilantSalience Network & Anterior InsulaDetects what matters in the body and environmentSimulates graviceptive cues without triggering panicAnchors awareness in the present momentBeing in the Moment—Taken SeriouslyHonnold’s survival depends on microsecond-level presenceNo anticipatory anxiety, no future projectionFinger placement, balance, and movement solved in real timePresence as an adaptive skill—not a sloganGravity Sensitivity as a ContinuumHumans vary widely in tolerance for heights, G-forces, and riskToo much fear → paralysisToo little fear → dangerHealthy functioning lies in the middle of the curveMental Gravity, Anxiety, and DepressionAnxiety = anticipation of fallingDepression = being stuck or weighed down in the presentHonnold represents the opposite extreme: calm within gravityInsights help reframe everyday anxiety as mis-tuned gravity perceptionTraining vs TalentHonnold combines rare inborn traits with years of intense trainingPhysical: extreme strength, precision, enduranceMental: emotional regulation, present-moment focusFear is not absent—it is managed and containedWhat Can We Learn (Safely)?Not to climb skyscrapers—but to train mental fitness:Cognitive Behavioural Therapy as mentaltrainingMeditation as present-moment conditioningBreathwork, yoga, and grounding practicesSocial connection and rest as recoveryBalancing effort and recovery (noovertraining)Mental fitness = something you work on, not something you either have or don’t have.One Percent RuleYou don’t need to be Alex HonnoldChanneling 1% of his presence, calm, and training can meaningfully improve everyday resilienceTimecodes00:00 — Emergency episode & skyscraper climb01:10 — Free Solo and gravity defiance02:15 — Watching the footage & bodily reactions02:45 — Fear, falling & butterflies03:30 — Amygdala findings04:20 — Anxiety, pain & hyper-vigilance05:10 — Salience network & graviception06:20 — Courage vs fearlessness06:50 — Gravity sensitivity across populations07:50 — Mental gravity & anxiety08:50 — Training, not recklessness10:00 — Being truly in the moment11:10 — Depression, anxiety & time orientation12:05 — Learning from extreme phenotypes13:20 — Mental health in a steeper world14:20 — Training for modern life15:20 — Mental fitness beyond CBT16:10 — Meditation, breath & balance17:35 — One percent of Honnold18:30 — Closing reflectionsResourcesThe Gravity Doctors: https://thegravitydoctors.comDr Brennan Spiegel: https://brennanspiegelmd.comDr Lachlan Kent: https://lachlankent.auBook — Pull: How Gravity Shapes Your Body, Steadies the Mind, and Guides Our Health

Dr Brennan Spiegel (physician, gastroenterologist, and author of Pull) and Dr Lachlan Kent (cognitive scientist and founder of Mental Gravity) explore serotonin as a gravity-management molecule, reframing it not simply as a “happiness chemical,” but as a fundamental biological system that allows life to stand up, move fluids, regulate balance, and remain psychologically buoyant in a gravitational field.Together, Brennan and Lachlan unpack new research on serotonin’s role across the gut, cardiovascular system, lymphatics, vestibular system, reproduction, and mood—showing how 95% of serotonin is produced in the gut, in symbiosis with the microbiome. They trace serotonin’s evolutionary origins from ocean life to land, altitude, and even space, and discuss practical implications for diet, exercise, sunlight, microbiome care, and mental health.1. What Is Serotonin?A whole-body gravity resilience molecule, not just a brainneurotransmitter Exists in two largely separate compartments: brain and gutCentral to movement, circulation, balance, mood, and vitalityEvolutionarily conserved across plants, animals, and humansSerotonin as a Gravity-Management SystemGut & DigestionMotility against gravity in any body orientationPumps & TubesBlood pressure regulation, cardiac contractility, lymphatic returnBalance& OrientationVestibular function; dizziness during SSRI withdrawalReproductionRetrograde uterine contractions that move sperm upward against gravityMood &EnergyMental elevation, vitality, resilience, and time perceptionThe Microbiome–Serotonin AllianceTrillionsof microbes are required to trigger serotonin productionThe gut as a “dark, sulfurous, hydrothermal” evolutionary nicheA symbiotic bargain: microbes get mobility; humans get serotoninChanges in altitude, microgravity, and spaceflight rapidly alter serotoninbiologySTACK TEN: The Anti-Gravity Diet (introduced)A practical framework from Pull for supporting serotonin production via tryptophan-rich foods.Core principles:Tryptophan as substrateMicrobiome diversityDietary balance rather than supplementation aloneTherapeutic & Self-Care ImplicationsDietary modification (tryptophan-rich foods, microbiome-supportive diets)Exercise and movementSunlight and time outdoorsWorking with dietitians for GI and mood conditions (e.g., low-FODMAP when indicated)Understanding limits and side effects of SSRIsNaturally supporting serotonin across body and mindMetaphor & MeaningThe gutmicrobiome as the “spice factory” of human biologySerotonin as the true “spice of life”—powerful, regulating, and double-edgedGravity as the organizing principle linking biology, psychology, and medicineTimecodes00:00 —Welcome & why serotonin matters01:10 — Serotonin beyond the “happiness chemical”02:20 — Gut vs brain serotonin compartments03:20 — Pumps, tubes & whole-body effects04:25 — Lymphatics, reproduction & balance06:20 — Evolutionary origins & gravitation08:10 — Microbiome symbiosis metaphor10:15 — Altitude, spaceflight & serotonin disruption11:30 — STACK TEN diet introduced12:45 — Diet, microbiome & mood disorders13:50 — Dune, spice & serotonin metaphor15:45 — SSRIs: benefits, limits & side effects17:00 — Natural serotonin support & integration17:45 — Closing reflections & next stepsResourcesThe Gravity Doctors website: https://thegravitydoctors.comDr Brennan Spiegel: https://brennanspiegelmd.comDr Lachlan Kent: https://lachlankent.auBook — Pull: How Gravity Shapes Your Body, Steadies the Mind, and Guides Our Health

In this episode, Dr Brennan Spiegel (physician, gastroenterologist, and author of Pull) and Dr Lachlan Kent (cognitive scientist and founder of Mental Gravity) dive deep into gravity resilience and introduce listeners to the new Gravitype Quiz—a wellness tool that blends biomechanics, neuroscience, and psychology to help people understand their personal relationship with gravity.Together, Brennan and Lachlan take the quiz live on the show and compare results, unpacking the three pillars of biogravitational health: gravity fortitude, gravity sensing, and mental gravity. Along the way, they explore back pain, dizziness, cold exposure, resilience, interoception, emotional balance, and how experiences like roller coasters or elevators reveal something about your gravitational tendencies.You can try the full interactive quiz here:brennanspiegelmd.comvirtualmedicine.org/pullthegravitydoctors.com1. What Is a Gravitype?A personalised profile of gravity resilienceBased on the framework in Pull and grounded in emerging concepts in biogravitational medicineNot a diagnostic tool — currently evidence-informed and intended for education/wellnessGravity FortitudeMuscles, bones, pumps, and tubesCardiovascular and postural strengthBack pain, leg swelling, stair climbing, grip strengthGravity SensingInner ear, proprioception, vestibular functionBalance tests (like one-leg standing)Cold sensitivity, interoception, dizziness/vertigoMental GravityWeighted-down vs upliftedStress tolerance, emotional recovery, “flow” statesDual-continuum model of mental healthGrip strength as a predictor of longevityBMI and physical load on the spineOrthostatic light-headedness and blood pressure regulationInner-ear disorders (e.g., BPPV) and sensory hypersensitivityThe anterior insula as the “gravity conductor” of the body–mind symphonyThey answer questions on:Opening a jarClimbing stairsBack painLight-headednessBalanceCold toleranceEmotional reactivity and resilienceRoller coaster sensitivityPositive emotional absorption (flow)Each reflects personally on past injuries, thyroid health, yoga, meditation, diet, travel, and evolving gravitational resilience across their lives.Durable fortitudeNormosensitive sensingLifted mental gravityNotes how training (cold exposure, yoga, flying) reshaped Lachlan's sensitivity over time.Reflections on vertigo, cold intolerance, and emotional uplift as part of Brennan's profile.Both discuss how gravitypes can change with training, awareness, and targeted practices.Examples include:Down-regulating sensory overload (slow nasal breathing, longer exhales, box breathing)Strengthening the gravity fortitude system (movement, posture, reducing sitting time)Noticing “watch-outs” such as back pain, dizziness, or emotional ruminationLinks included in the show notes.00:00 — Welcome, origins of the gravitype01:30 — Gravity resilience basics03:00 — Gravity fortitude (muscles, tubes, pumps)06:45 — Mental gravity explained08:00 — Starting the quiz09:00 — Grip strength & longevity11:00 — Stair climbing & cardiovascular load12:00 — Back pain & evolution15:00 — Orthostatic dizziness & fainting18:00 — BMI, weight, and gravitational load20:00 — Leg swelling, pumps & tubes23:30 — Gravity sensing & vertigo25:00 — Balance tests (one-leg stance)26:30 — Cold sensitivity & nervous-system tuning29:30 — Interoception & the anterior insula33:00 — Stress, heaviness & mental gravity36:00 — Roller coasters, turbulence & fear responses38:00 — Emotional resilience and bouncing back41:00 — Flow states and uplift43:00 — Revealing their gravitypes46:30 — What their results mean48:00 — Final reflections & where to take the quizThe Gravity Doctors website: https://thegravitydoctors.comGravitype Quiz: available on BrennanSpeigelMD.com & virtualmedicine.orgDr Brennan Spiegel: brennanspiegelmd.comDr Lachlan Kent: lachlankent.auBook — Pull: How Gravity Shapes Your Body, Steadies the Mind, and Guides Our Health

In this uplifting and deeply human episode of The Gravity Doctors, Dr. Brennan Spiegel (Cedars-Sinai gastroenterologist and author of PULL) and Dr. Lachlan Kent (cognitive scientist and theorist of Mental Gravity) sit down with Harmon Clarke, a patient-turned-researcher whose remarkable recovery story illuminates the future of biogravitational medicine.From septic shock and 200 days in hospital to yoga teacher, breathwork practitioner, and health researcher, Harmon’s journey embodies resilience, creativity, and the healing power of re-engaging with gravity. Together, they explore how movement, inversions, virtual reality, and breathwork can transform pain and depression into buoyancy and balance — culminating in a spontaneous “Gravity Rap” that captures the spirit of the show.Core ThemesGravity as a unifying metaphor for physical and mental healthMovement and inversion therapy for resilience and recoveryVirtual reality and embodied cognitionTensegrity, balance, and the biomechanics of wellbeingPatient empowerment and the hero’s journey in healingBiogravitational medicine as a synthesis of East–West paradigms00:00 – Welcome and Introductions01:00 – Facing the Grave03:00 – Virtual Reality and the Mind–Body Connection06:00 – Yoga, Breathwork, and Natural Recovery08:00 – The Science of Inversion and Tensegrity14:00 – Hospitals and Gravity Intolerance18:00 – Depression as a Gravitational Condition24:00 – Cathy Freeman and Gravitational Flow25:45 – East Meets West30:00 – Rebalancing Medicine33:00 – The Simple Tools of Healing35:00 – Designing the Future of Biogravitational Medicine38:00 – Generational Health and Modern Comfort41:00 – The Gravity Rap Finale Order Brennan's book "Pull" to learn more about how gravity shapes your health in both body and mind via his personal ⁠⁠personal website⁠⁠.Visit ⁠⁠Lachlan's website ⁠⁠to learn more about his work in mental gravity. Music by ⁠ALLIRA⁠ and Visceral SoundRecording at JTB Studio by David Iskandaryan. Editing by Dr Karisma Suchak.

Dr Spiegel has written a book about gravitational health called 'Pull' on the wide ranging themes underpinning this podcast - gut health, mental gravity, serotonin, the inner ear, the body's pumps and tubes, the gravitostat, and many more. The hosts take a tour through the world of biogravitational medicine by telling the story of what inspired the book, where the science is heading, and how people can apply the principles in their daily lives.Order Brennan's book "Pull" to learn more about how gravity shapes your health in both body and mind via his personal personal website.Visit Lachlan's website to learn more about his work in mental gravity.Music by ALLIRA and Visceral Sound.This episode was recorded at Myst Music.Thanks to Jeremy Roberts for audio engineering and Dr Karisma Suchak for editing.