The Gravity Doctors

All loved "UP" on Valentines Day: Gravity and cuffing season

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

How the Brain Senses Gravity — with Elisa Ferrè

Dr Lachlan Kent and Dr Brennan Spiegel are joined by Elisa R. Ferrè, professor of cognitive neuroscience at Birkbeck, University of London, and one of the world’s leading experts on graviception and the vestibular system.Together, they explore how the brain senses gravity without a single “gravity receptor,” why the vestibular system has no primary cortex, and how gravity is computed as a distributed, multisensory model integrating vestibular, visual, proprioceptive, and visceral signals. The conversation spans neuroscience, emotion, aesthetics, culture, spaceflight, and mental health—revealing gravity as the hidden scaffolding of perception, meaning, and wellbeing.1. What Is Graviception?The brain’s ability to sense and model gravityNot driven by a single receptor or cortical areaConstructed through multisensory integrationFundamental to embodiment, orientation, and survivalWhy the Vestibular System Is UniqueNo unimodal “vestibular cortex”Projects broadly across the brainDoes not produce a clear conscious sensationBecomes noticeable mainly when something goes wrong (dizziness, vertigo, nausea)The vestibular system acts as the glue binding mind and body, anchoring us in a single embodied perspective.How the Brain Computes GravityGravity is not perceived directlyThe brain integrates:Vestibular otolith signals (head tilt, linearacceleration)Visual cues (verticality, alignment)Proprioception (joints, muscles, posture)Visceral signals (internal organs)Each signal is weighted by reliability to form an internal model of terrestrial gravity.Gravity, Meaning, and CulturePreferences for verticality (upright lines, tall buildings)Vertical = power, stability, positivityDownward tilt = unease, disorderGravity shapes art, architecture, language, and metaphorUp = good, free, elevatedDown = heavy, negative, constrainedEmotion, Fear, and the Vestibular SystemVestibular pathways connect directly to:AmygdalaInsulaHypothalamusThis explains why vestibular disturbances are emotionally chargedDizziness and vertigo trigger fear, nausea, and autonomic responsesGravity sensing is deeply tied to survival systemsWeightlessness and FreedomParabolic flight (“vomit comet”) as a unique graviceptive stateWeightlessness described as profound freedomAlso physiologically challengingPost-flight “down” feelings mirror return to gravityFreedom comes with a cost: sensory conflict and adaptation demands.Space Adaptation & NeuroplasticityAstronauts experience space motion sicknessSymptoms: nausea, disorientation, brain fogThe brain can adapt through neuroplasticityAdaptation takes time, energy, and trainingImplicationsfor long-term space travel and Mars exploration.Gravity, Mental Health, and Everyday LifeAnxiety as mis-tuned gravity anticipationDepression as altered temporal and bodily groundingMental fitness as trainable gravity resilienceTools discussed:Yoga and postureBreath awarenessGrounding through the feetWeighted blanketsMusic, rest, and multisensory regulationPractical Graviceptive TipStand still and feel the pressure through the soles of your feetNotice the security of 1GUse grounding as a way to reduce anxiety and reset expectationsTimecodes00:00 — Introduction & guest welcome02:00 — What makes the vestibular system unique05:00 — Why gravity is mostly unconscious06:30 — How the brain computes gravity09:30 — Homunculus vs gravity computation11:30 — Gravity as a prior for perception14:00 — Semantics, aesthetics & verticality17:00 — Architecture, art & meaning20:00 — Vestibular system & emotion22:00 — Parabolic flight & weightlessness24:00 — Freedom, addiction & the cost of zero-G28:30 — Space adaptation syndrome31:00 — Can humans adapt to Mars?35:30 — Everyday graviception & grounding38:00 — Closing reflectionsResourcesThe Gravity Doctors: https://thegravitydoctors.comDr Brennan Spiegel: https://brennanspiegelmd.comDr Lachlan Kent: https://lachlankent.au

EMERGENCY EPISODE: Alex honnold’s incredible gravity-defying climb

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

Defying Gravity: The Olympics and the Limits of Human Performance - Ep 9

How do elite athletes use body, mind, joy, and meaning to push beyond physical limits? Dr Brennan Spiegel (physician, gastroenterologist, and author of Pull) and Dr Lachlan Kent (cognitive scientist and founder of Mental Gravity) explore theOlympics as humanity’s greatest laboratory for defying gravity.With the Winter Olympics approaching, they examine elite athletes as “physics-fighting engines”—bodies and minds trained to resist, redirect, and sometimes seemingly escape gravity. Through stories of Cathy Freeman, Quincy Hall, Alex Honnold, and modern superstars like Steph Curry and Luka Dončić, they show how peak performance is not just physical—it is mental gravity management.They introduce Olympic training as a real-world expression of biogravitational medicine, where strength, balance, imagery, joy, poise, team culture, and meaning all shape how far humans can push their relationship with gravity.1. Why the Olympics Matter to Mental GravityThe Olympics showcase humanity at the edge of physical limitsElite sport = everyday gravity management taken to extremesAthletes model what it means to fight gravity physically and mentallyPeak performance = synchronization of body, brain, and meaningAthletes as Anti-Gravity PrototypesCathy Freeman (Sydney 2000)“Floating” to gold in the 400mHome crowd as acceleration, not pressureUp, light, fast = opposite of depressionQuincy Hall (Paris 400m Final)Turning failure into flightLast-minute mental reversal → physical transcendenceBasketball, Ski Jumping, SkatingLeaping, flying, spinning, managing G-forcesAngular momentum and rotational control as gravity masteryMental Gravity in Elite PerformancePerformance depends on mental poise, not just muscleStillness before actionPressure as fuel, not burdenCrowds as acceleration, not oppressionJoy as a performance amplifierExamples:Steph Curry — joy + precisionLuka Dončić — playfulness under pressureAsh Barty — recovery from “the yips” through joyImagery, Rehearsal, and GravityMental imagery as bodily rehearsalKyrie Irving visualizing free throwsAlex Honnold mentally climbing El Capitan before climbing itMental gravity = using body as template for thought and emotionUp = energizedDown = heavyCalm = balancedFear, Falling, and MasteryFear of falling = gravitational anxietyElite athletes train to feel secure within gravityButterflies in the belly = falling sensationsGreat athletes use fear to prime—not paralyze—the nervous systemTimecodes00:00 — Welcome & why the Olympics matter01:00 — Peak athleticism as defying gravity02:00 — Cathy Freeman & floating to gold03:30 — Winter sports & G-forces04:30 — Quincy Hall’s last-minute flight06:00 — Mental vs physical performance07:30 — Stillness, pressure & acceleration09:00 — Joy as a performance tool10:30 — The yips, anxiety & recovery12:00 — Mental imagery in sport13:30 — Kyrie Irving & visualization14:45 — Alex Honnold & fear mastery16:15 — Fear, falling & butterflies17:45 — Biogravitational training stacks19:00 — Team culture & social gravity20:30 — VR, the Proteus Effect & training22:00 — Dead hangs & gravity endurance24:00 — Olympics as humanity’s gravity experiment25:00 — 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

Serotonin: The Body’s Anti-Gravity Molecule - Ep 8

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