The Weight We Carry: How We Rise Against Gravity Before Returning to the Earth

Brennan Spiegel, MD

Gravity was here long before we were, and it will be here long after we’re gone. It is steady, relentless, indifferent. It does not negotiate or take days off. It has no moral standing or opinion of what we deserve. It simply pulls. Every sinew, every cell, every fiber of our being was sculpted in response to this force. Physics came first; biology second. In that sense, every living thing is a story written in the language of gravity.

We begin life trying to rise into this invisible field, and we end life returning to it. Even the words grave and gravity share the same root—literally, “to weigh down.” That shared origin is not a coincidence of linguistics. It reflects a deeper truth: to live is to rise against this pull, to carry its weight, and eventually to surrender to it when our bodies can no longer resist.

We may think of gravity as a matter for astronomers or physicists. But gravity is the most powerful healthcare challenge we all face. It shapes how we move, how we digest, how we circulate blood, how we feel emotions, and even how we perceive our own dignity. In the clinic, I’ve come to see it not merely as a physical force, but as an organizing principle for our biology and our inner lives—not just something we live under, but something we live within.

That realization came to me in an unexpected place: around a dinner table. After years of practicing medicine, teaching students, and leading research on the mind–body connection, I was startled to discover that I had missed something hiding in plain sight. A quiet moment with my family opened a door I didn’t know existed, pulling me into a line of inquiry that reshaped my work, changed how I think about health, and eventually compelled me to write an entire book on how gravity shapes human well-being.

But that turning point didn’t arrive as a scientific epiphany

It began as a simple question my wife asked me about her mother.

When Gravity Gains Ground

My mother-in-law had recently moved into an assisted living community and soon developed bloating, discomfort, and a sluggish gut—symptoms that didn’t seem tied to any obvious change. Her diet was the same. Her medications were stable. And yet she felt heavier—physically and emotionally—carrying a weight she couldn’t name. Since my expertise is in gastroenterology, my wife turned to me for insight.

What had changed was her relationship to gravity. She was spending much of the day lying down or sitting for long stretches with little movement. Slowly, she was weakening not only in body but in spirit. Her posture sank, her energy dimmed, her pain worsened, her balance faltered, and the low mood that had crept in after the move began to deepen. And that worried me, because without standing and moving, everything begins to slow—the gut, yes, but also the pumps and tubes of the cardiovascular and lymphatic systems, the nerves that help us balance against gravity’s constant tug, always waiting to pull us down the moment we stop paying attention, the muscles and bones that hold us upright, even mood and cognition. Humans aren’t meant to lie flat all day. We’re built to stand up.

I worried she was giving in to gravity.

The human body is designed for a vertical world. Our organs, vessels, nerves, and connective tissues all evolved to function under the gentle but continuous downward pull that shapes circulation, digestion, posture, and alertness. When we spend too much time horizontal, peristalsis slows, blood and lymph pool, posture collapses, muscles atrophy, bed sores break through the skin, blood clots form in the legs, balance deteriorates, and mood and clarity fade. This is why the bedridden so often struggle with digestion issues, swelling, instability, and emotional decline. Simply helping someone spend more time upright—even in small increments—can help stimulate the body, lift mood, and reactivate systems that drift toward dormancy when we slip too close to the ground.

Her body was quietly losing its dialogue with gravity—a dialogue our biology expects every single day.

That observation sent me down a long path of research that eventually became a peer-reviewed medical paper called Gravity and the Gut. At first, I hesitated even to write it. As a professor and dyed-in-the-wool academic, I worried the idea might sound too speculative—as though I’d drifted too far from traditional medicine. But the more I looked, the more I saw patterns I couldn’t ignore. Maybe there was a tighter link between the physics of our world and the physiology of our bodies than I’d ever imagined. And why shouldn’t there be? We are shaped by our environment, and gravity shapes everything in it—including us.

When the paper went to press, I expected a small scientific ripple. Instead, it triggered a wave. Within days, outlets like Newsweek, Popular Science, and the Daily Mail were running stories about the idea, each putting its own spin on how gravity might underlie a wide range of symptoms. The headlines were bold, sometimes playful, sometimes over the top—but they spread the core message beyond anything I had anticipated.

Hundreds of people wrote to say the idea made sense of symptoms they’d carried for years. Some described dizziness or vertigo that felt like an “allergy to gravity.” Others shared how inverted yoga poses, standing desks, abdominal exercises, wedge pillows, or even changing sleeping positions brought unexpected relief. A few reported gut symptom triggered by air travel, high-altitude drives, roller coasters, or even playground swings.

The question was no longer whether gravity affects us.

It was: How deeply does this force govern who we are?

Standing Up Is Our First Revolution

Human evolution is a story of learning to stand. Most of our brain development is not simply about thinking, but about controlling posture, balance, and coordinated movement in a gravity-bound world. We are born horizontal, but spend childhood learning to rise. When we take our first steps, parents gasp not only because it is adorable, but because it is a victory against a fundamental force. We recognize instinctively that something profound has happened when a baby stands. A new phase of life begins.

From that first moment onward, everything we do—from eating to speaking to embracing others—is shaped by our ability to keep our heads above the ground. So much so that standing has become synonymous with autonomy, confidence, and resolve.

We “stand up” for ourselves. We “stand tall” when proud. We take a “stand” when we refuse to back down. When someone dies, we say they “fall.” When someone suffers emotionally, we describe them as “down.” Our metaphors are not poetic coincidence; they are subconscious physiology. Language reveals our neurobiology. The brain maps physical height to safety, competence, and vitality, and maps downward motion to vulnerability, illness, and decay.

This is not only metaphorical. Depression can literally feel heavy in the body. Time can feel slowed, limbs heavy, posture dragged toward the ground. Australian neuroscientist Lachlan Kent calls this phenomenon “mental gravity,” a distortion in how we sense the force that holds us to the Earth. Joy, love, and awe can feel “uplifting” because our nervous system perceives a change in gravity’s tug—not in physics, but in physiology.

To stand up is therefore not only a musculoskeletal act, but a psychological and existential one. A refusal to collapse before we must.

Resistance as Health

If gravity wants us on the ground, we can only stay up by learning to resist. But resistance isn’t static. We get better at it when we practice.

Take astronauts. In orbit, freed from gravity, their bodies quickly deteriorate. They lose bone mass, muscle, cardiovascular function, lymphatic flow. NASA requires two or more hours per day of rigorous exercise aboard the International Space Station because, without resistance, the body unravels. Space is a laboratory of disintegration.

But the reverse is also true. By adding load—carrying weight, training muscles that fight gravity—we can become stronger than we thought possible. I learned this firsthand when I spent eight weeks living as if Earth had heavier gravity. I strapped a 20-pound vest and 10-pound ankle weights to my body and worked at my standing desk all day, much to the amusement of friends and colleagues. At first, I ached. Yet as days passed, my legs strengthened, my posture improved, I lost weight without changing diet, and even old neck pain eased.

The key wasn’t just exercise. It was purposeful confrontation with gravity.

Scientists recently discovered a system in our bones called the gravitostat—a weight-sensing mechanism that influences appetite and metabolism. Rats and humans who carry extra load tend to lose fat but preserve muscle, a principle behind the rising practice of “rucking,” or walking with weighted backpacks. In other words, the body listens to the pull of the Earth and adjusts accordingly.

To thrive physically, we must resist. The force that pulls us down also gives us something to push against. Our goal in life is to stand up and stay up, for as long as we can, and as well as we can—until, eventually, we are pulled back. And the body feels that pull—not just in our bones and muscles, but even in our bellies. Gravity reminds us of itself every time it yanks us downward, every time a dip or drop makes our stomachs flip. That tug is not merely metaphorical; it’s physiological.

The Gut: A Gravity Alarm

As a gastroenterologist, I am attuned to the gut’s alarm systems. And none is more ancient or universal than the sensation of falling.

A roller coaster drop, a sudden lurch in an elevator, even tripping for a split second—these moments trigger a deep, visceral warning in the belly. Butterflies in the stomach are not poetic flourish. They are signals from our g-force detection system, buried deep in the body, evolved to keep us from harm. The gut is our barometer of stability, constantly scanning for threats to our upright existence.

Our emotional lives use the same circuitry. “Falling” in love, for example, is literally destabilizing and can cause those same butterflies in the belly as falling on a rollercoaster. It exposes us, elevates us, and makes us vulnerable. The same neural pathway that warns us when standing at the edge of a cliff fires when we risk intimacy. The belly doesn’t distinguish between physical and emotional altitude.

The gut, in this view, is not just digestive plumbing. It is a sentinel of stability.

This is why practices like grounding meditation, diaphragmatic breathing, and cognitive behavioral therapy can soothe not just anxiety, but the body’s gravitational alarm. Many people living with gut discomfort or tension find that when they calm the mind—through meditation, breathing practices, or mindfulness—the body softens too, as if the inner alarms finally have permission to settle. By steadying the mind, we steady our posture, breath, muscles, and viscera in ways that make us feel safer in the world.

But the more I thought about these signals, the more I found myself searching for what linked them all together. Hippocrates famously said that all disease begins in the gut—but what did he mean? Why is it that when the gut falters, people don’t just feel it in their abdomen, but everywhere? Brain fog, dizziness, anxiety, depression, aches and pains, drops in blood pressure, difficulty standing upright. It was as if the gut wasn’t merely processing food; it was acting as a gravity-sensing hub wired into every major system of the body. And that raised a deeper question: what kind of biology is so sensitive to gravity that a small disruption in the belly can ripple all the way to the brain?

The search for that answer led me to serotonin.

Serotonin: The Molecule That Helps Us Stay Upright

We tend to think of serotonin as a mood chemical. But serotonin’s deeper purpose is to help us navigate gravity. More than 95% of it is produced in the gut, not the brain, in partnership with trillions of microbes. Without this supply, simple tasks like standing without fainting or maintaining balance without sudden dizziness would become challenging. Our muscles and bones would lose their coordination in response to gravity’s demands, leaving us unsteady and prone to palpitations. Our lymphatic system would struggle to clear toxins and circulate immune cells, leading to swelling and vulnerability to infection. Life on Earth would be a major struggle without serotonin.

Zooming out, serotonin reveals itself as a kind of gravity-management substance—fueling the same networks that keep us vertical. It supports muscle tone, modulates inner-ear balance, stabilizes blood pressure when we stand, supports muscle tone, regulates lymphatic and venous return against gravity. And yes, it also “elevates” mood (another gravitational idiom), in part because mood is tied to physical equilibrium. Without serotonin, we wouldn’t just feel sad; we would feel heavy, unstable, and unable to rise.

But nature has a plan, one that involves the microbial universe living inside us. These microscopic allies ensure a steady supply of serotonin. Thanks to this partnership, we can stand tall, move with precision, and navigate life’s challenges—all while contending with the constant force tethering us to Earth. From an evolutionary perspective, it’s as if we struck a bargain with these microorganisms: we offered them a warm, wet, dark, gassy, and sulfurous world—much like the deep-sea hydrothermal vents where life may have first emerged—and in return, they gave us the ability to move across a gravity-bound globe, carrying them farther than their tiny forms could ever travel alone.

This evolutionary bargain does more than keep us upright; it reframes the surprising connection between our place on Earth, the microscopic life within us, and the neurochemicals that regulate our health. It reveals a deep interplay between environment and physiology—a reminder that we are not passive inhabitants of this planet but are woven into it, right down to the cellular and molecular levels. And once you see that connection, a lot of puzzling things start to make sense: why mood and balance are intertwined, why gut problems ripple into the mind and muscles, why altitude affects some people more than others, and even why serotonin-based medications like SSRIs can help steady both emotional and physical equilibrium. Once you recognize serotonin as yet another way the body negotiates with gravity, the practical implications become clear.

It also casts light on how to nurture serotonin without medication. Slow breathing stimulates the vagus nerve, which boosts serotonin release. Singing, chanting, cold-water splashes, and sunlight activate the same pathway. Movement, yoga inversions, standing breaks, and balance training strengthen the muscles and nerves that manage gravity. Tryptophan-rich foods—turkey, chicken, eggs, cheese, nuts, seeds, tofu, salmon—feed the microbial factory that makes serotonin in the first place.

When you nourish your gut, you create serotonin. When you create serotonin, you lighten gravity’s load on body and mind.

This connection between gravity and inner equilibrium doesn’t end with biology; it even extends into how cultures express reverence, grief, humility, and strength through posture.

Spiritual Posture

Across cultures, posture has always been linked to spiritual life. Jewish tradition, for instance, is rich with physical rituals that embody humility, dignity, and relationship to the ground. We bow on Yom Kippur, kneel in moments of contrition, rise to read sacred text, and stand together to honor the Amidah prayer—a communal acknowledgment of presence and uprightness.

During mourning, we sit on low stools for shiva, lowering ourselves closer to the ground as a physical symbol of sorrow. We do not stand tall in grief. We descend. Our bodies know what words struggle to say: loss pulls us down. Over time, standing again becomes a quiet act of healing.

These rituals are intuitive expressions of a shared biology. Posture is a vocabulary of the soul, shaped by gravity long before language arrived. To kneel, to bow, to stand, to sink—these motions echo our evolutionary journey as creatures that rise, resist, and eventually return to the Earth.

To live well is not to escape gravity. It is to move with it.

The Weight We Carry

In the end, gravity wins. We all return to the ground. The question is not whether we fall, but how we spend the time between standing and surrendering.

Every day we are given a chance to practice resilience—not to build strength as armor, but as alignment with our environment. We can nourish the microbes that make serotonin, move with intention, let the gut settle its alarms, breathe into our posture, stand taller when it feels difficult, kneel when it is appropriate, sit low when we grieve, and rise again when we are ready.

Master this one relationship—our relationship with gravity—and every other act of living becomes easier. Health is not just surviving illness or adding years. It is learning to rise against the pull of the Earth with grace, stubbornness, curiosity, and reverence for the force that shapes us.

We are born horizontal. We spend our lives fighting to stand. And when that struggle ends, the Earth embraces us again—just as the Torah teaches that we return to the dust we came from, not as defeat, but as closure. The weight returns to the source of weight. The ground that challenged us ultimately receives us, completing a cycle written into our biology long before our first breath.

Until then, we live by resisting what pulls us down.

Not to escape it.

But to grow against it.

From the Author

This essay is adapted from his book PULL: How Gravity Shapes Your Body, Steadies the Mind, and Guides Our Health (St. Martin’s Press, 2025). Available wherever books are sold.

Author’s note: I wrote this essay using good old-fashioned human intelligence. After writing the text, I employed Chat GPT-5 to help copyedit my original passages. I believe it remains important that humans—not computers—think and write for other humans, but also recognize benefits of AI to support editing of original text written by humans. I also believe it is important to be clear about whether, when, and

how AI is used when preparing text for publication.