The 1000 Hours Outside Podcast: Episode Summary
Episode: 1KHO 592: Gravity Intolerance Might Be Your Missing Link | Dr. Brennan Spiegel
Host: Jenny Urch
Guest: Dr. Brennan Spiegel, Professor, Gastroenterologist & Author of "Pull: How Gravity Shapes Your Body, Steadies the Mind, and Guides Our Health"
Release Date: October 8, 2025

Overview

In this fascinating and wide-ranging episode, host Jenny Urch speaks with Dr. Brennan Spiegel about his groundbreaking work exploring how the force of gravity affects human health, childhood development, mental well-being, and even the functioning of our gut. Drawing from his new book, "Pull," Dr. Spiegel introduces the concept of "gravity intolerance" and discusses how our increasingly sedentary, indoor lifestyles may be undermining our physical and psychological resilience. The conversation weaves together practical advice for parents, illuminating scientific explanations, personal anecdotes, and actionable suggestions on how to reclaim the health benefits of gravitational engagement — particularly through outdoor play.

Key Discussion Points & Insights

1. Concept of Gravity Intolerance

• Gravity as a Hidden Force:
  Dr. Spiegel compares humans’ relationship to gravity as akin to a fish’s relationship with water—rarely noticed, but fundamentally essential.

  "Our relationship to gravity is kind of like a fish to water... I doubt the fish thinks much about water at all."
  — Dr. Spiegel [01:53]

• Anecdotal Genesis:
  Inspired by observing his mother-in-law’s health decline after moving to assisted living (increased lying down, decreased movement), leading him to study the health impacts of gravity’s “absence.”

• Medical Validation:
  Initially worried his theories were too “out there,” he shared his research with global experts, only to find his thinking resonated and quickly got published.

2. Movement & Modern Lifestyle

• Sedentarism and Children:
  Modern children sit an average of eight hours per day—far more than previous generations.

  "The sedentary lifestyle is leading to health problems...in relation to our kids, gravity intolerance means we need to get our kids physically moving.”
  — Jenny Urch [04:02]

• Counteracting Sedentarism:
  Dr. Spiegel uses a standing desk, balance board, weighted vest, and ankle weights to “fight gravity” in his daily life, recommending dynamic movement (“proprioceptive training,” “eccentric movements”) for kids and adults.

3. Self-Experiments: Operation Gravitate

• Wearing Extra Weight:
  Wearing 40 pounds of weights for eight weeks changed not just Dr. Spiegel’s body but his mindset:

  "A new strength was growing, not just in my muscles, but in my spirit. It forged a sturdier and more vibrant self."
  — Dr. Spiegel [10:54]

• The body’s “gravitostat” can increase metabolism simply by weighing oneself down temporarily (e.g., with weighted vests or rucking).

• Feeling of buoyancy and ease after removing weights compared to baseball players’ weighted bats—training with gravity builds overall strength.

4. Mind, Mood & Gravity

• Graviception & Mental Health:

  • Depression can feel like excessive gravity—slumping, exhaustion, heaviness.
  • “Graviception” is the brain’s internal sense of gravity; a disrupted relationship may contribute to both depression and anxiety.
  • Posture and standing tall have physiological and psychological benefits:

    “Standing tall doesn’t just make you look confident. It also brings positive thoughts to the forefront, while slouching has the opposite effect.”
    — Jenny Urch [13:58]

• Metaphors in Language:
  The language of mood and aspiration (rise, fall, climb the ladder) is imbued with gravity-centric concepts:

  “For someone with depression, the literal and metaphorical challenge is simply to rise.”
  — Jenny Urch [13:08]

5. Feet, Grounding, and Footwear

• The "Gravity Management Surface":
  The sole of the foot, despite being only 5% of the body surface, bears 100% of our weight.
  Over-padding with modern shoes disconnects us from tactile feedback.

• Switching to Barefoot Shoes:
  Dr. Spiegel shaved 20 minutes off his marathon time with barefoot-style shoes, improving foot strength, arches, and posture. He encourages parents to consider less-cushioned shoes allowing for better foot engagement for children.

6. Gravity, Digestion, and Altitude

• Gut Health & Microbiome:
  Changes in gravity—such as those experienced in flight or at altitude—alter gut pressure and can trigger discomfort or bloating ("jet belly").
  The microbiome, which supports serotonin production, is affected by altitude and lack of gravity (as observed in astronauts).

  "Serotonin, I believe, is a gravity management substance."
  — Dr. Spiegel [23:39]

• Implications for Children Outdoors:
  Altitude hikes and swings affect gut function; children with gut issues may be more sensitive during such activities.

7. Astronauts and Bone Health

• Astronaut Health Problems:
  Despite being the healthiest among us, astronauts often return from space with headaches, bone loss, immune issues, and "jet belly" due to lack of gravity’s pull.

• Bone Loading in Childhood:
  Activities involving lifting, carrying (kids carrying pumpkins, parents carrying children), and dynamic movement stimulate bone-building cells (osteoblasts) and prevent bone loss.

• Rucking as Natural Exercise:
  Carrying children, as in traditional societies, preserves bone health and increases metabolism.

8. Vestibular Sense, Balance, and Ear Crystals

• The Vestibular System as the Glue of Mind-Body:

  • The vestibular (inner ear) system provides critical feedback for balance and self-location in space ("glue binding the mind to the body").
  • Dr. Spiegel’s own experience with a dislodged "ear crystal" (otolith) after a childhood concussion led to vertigo and insight into the mind-body link.
  • Simple maneuvers (like the Epley maneuver) can restore ear crystal balance and stability.

  “It tells you that you are you.”
  — Dr. Spiegel [32:47]

• Importance of Play:
  Childhood activities like somersaults, cartwheels, swings, and balance challenges train the vestibular system, which impacts physical and psychological health.

  “One of the purposes [of play] is literally to, as you said, be somersaulting, moving, cartwheeling, learning about your body in relationship to this earth.”
  — Dr. Spiegel [38:42]

9. Gravity’s Role in Anxiety and Gut Feelings

• Rollercoasters as Practice for Life:
  The gut sensations on a rollercoaster are the same as those experienced with performance anxiety or panic—“practicing our demise in a safe way.”

• Gut-Brain Axis: The gut, brain, and gravity all interact. Gut feelings can indicate real or psychological threats; chronic gut pain without medical explanation can arise from this axis.

  “The brain is a ventriloquist that is throwing its voice into the gut.”
  — Dr. Spiegel [49:14]

10. Practical Strategies and Action Steps

• Optimizing Gravity Engagement:

  • Use standing desks, balance boards, and weighted vests
  • Incorporate outdoor and dynamic play daily for children
  • Choose more natural footwear for better grounding
  • Try exercises like "dead hangs," squats, push-ups, and tai chi/yoga
  • Care for the vestibular system through movement and balance activities—even as adults

• Language, Mindset, and Identity:
  Recognize how “up” and “down” metaphors permeate health, mood, and aspiration.

• Biogravitational Medicine:
  Dr. Spiegel introduces this new lens for understanding health—tying evidence-based medicine to humanity's relationship with gravity.

Notable Quotes & Moments

• On the Ubiquity of Gravity:

  "This physics of our planet came first, and our biology came second. And then our psychology emerged from that." — Dr. Spiegel [01:53]

• On Sedentary Medicine & Healing:

  "...lying flat can be a double-edged sword when you're sick... we're not built to lie down all day."
  — Jenny Urch [07:04]

• On Strength and Spirit:

  "A new strength was growing, not just in my muscles, but in my spirit. It forged a sturdier and more vibrant self."
  — Dr. Spiegel [10:54]

• On Posture and Mental Health:

  "Standing tall doesn't just make you look confident. It also brings positive thoughts to the forefront, while slouching has the opposite effect."
  — Jenny Urch [13:58]

• On Play and Vestibular Training:

  "What is the purpose of play?... Be somersaulting, moving, cartwheeling, learning about your body in relationship to this earth."
  — Dr. Spiegel [38:42]

• On Biogravitational Medicine:

  "I call this biogravitational medicine. It's just a new way of thinking about...evidence-based medicine...tying it back to why it works in relation to gravity."
  — Dr. Spiegel [55:15]

• On Yawning as a Gravity Tool:

  "When you yawn, I see it as a gravity management tool...You suck in air...gravity pulls the blood to the base of the lungs...oxygenated blood flow to your brain just when you need it."
  — Dr. Spiegel [55:25]

Important Timestamps & Segments

• Gravity Intolerance Origins: [01:53]
• Operation Gravitate/Weight vests: [08:07]
• Gravity’s Role in Mind-Body Health: [10:54]
• Movement, Shoes, and Grounding: [15:20]
• Gravity, Gut Health, and Altitude: [23:39]
• Astronauts and Bone Density: [28:24]
• Vestibular System and Play: [32:47, 38:42]
• Rollercoasters, Anxiety, and Gut-Brain Axis: [43:10, 49:14]
• Biogravitational Medicine, Action Steps: [54:36]
• Yawning as Gravity Management: [55:22]

Actionable Insights & Parental Guidance

• Prioritize unstructured, dynamic outdoor play for children to develop a healthy relationship with gravity, proprioception, and the vestibular system.
• Incorporate weighted movement (rucking, carrying kids, walking with backpacks) into everyday family life.
• Use standing desks and balance tools for adults and children alike; limit prolonged sitting.
• Select footwear that permits natural foot movement and offers ground feedback.
• Be alert to signs of vestibular dysfunction in children (reading issues, balance complaints)—consider evaluation or vestibular exercises.
• Recognize the intertwining of body and mind—changes in mood, anxiety, or gut symptoms may sometimes reflect disrupted engagement with gravity.
• Frame activity not just as "exercise," but as essential gravitational training.

Closing Memorable Moment

Favorite Childhood Outdoor Memory
Dr. Spiegel recalls childhood visits to the Santa Monica pier, reflecting on the sensory and emotional richness of being at the boundary of “gravity-bound land and the buoyant world of the sea”—a perfect encapsulation of his message about the value of diverse, active, and sensory-rich outdoor experiences. [58:54]

Book Mentioned:
"Pull: How Gravity Shapes Your Body, Steadies the Mind, and Guides Our Health" by Dr. Brennan Spiegel

Final Reflection by Jenny Urch:

"It is remarkable how you took the whole concept that most people have never heard of, and you were able to explain the whole concept for just your average reader... and tie in all these other things—like the emotional parts of it and anxiety and depression, the vestibular sense, your own stories, and then... 'here's all sorts of things you can do.'" [57:58]

For Listeners:
This episode is more than a science lesson—it’s a call to action to help your children, and yourself, stand tall, move freely, and reclaim your place in the gravity-bound world.