Inner Nature

Our other pillars look outward, to the land, the water, and the air we are working to protect. This one looks inward, to the nature we are made of.

Step off the pavement and onto a trail, and something in you changes before you have decided to feel anything. The shoulders come down. The breath, without instruction, goes lower and slower. The running commentary in the head, that endless list of tasks and worries, drops by a notch, as if someone eased a dial. We tend to call this relaxation and leave it there, a pleasant vagueness, a nice mood. It is something more precise than that. It is your body recognizing a place it was built for.

Every other pillar on this site is about the nature outside us: the forests and farmland, the rivers and coastline, the built world and the energy that runs it. This one is about the nature we happen to be. Because for all our roads and roofs and glowing screens, we did not stop being animals. We are still made of water and rhythm and living cells, still tuned to the turning of a planet and the light of a single star, and the body we carry through our days still expects, and still quietly asks for, the world it evolved inside.

You are the middle of the chain

There is a sentence elsewhere on this site, in the pages on our ecosystems, that turns out to be the key to this whole idea:

A healthy cell sits in a healthy organ in a healthy body in a healthy family in a healthy community in a healthy bioregion in a healthy ecosystem on a healthy planet. And it goes the other way around. If we do anything that is unhealthy at any of those levels, it affects health at all the other levels.

Read it slowly, and notice where you are in it. Not at the top, not at the bottom. The body sits in the middle of that chain, one link among many, a whole world in itself and also a small part of a larger one. There is a young field of medicine built on exactly this insight. It is called planetary health, and its close cousin, One Health, treats the wellbeing of people, animals, and the living world as a single connected system rather than three separate subjects. What both are really saying is what that sentence already said: the links are not metaphors. They are load bearing.

And the most important words are the quiet ones in the middle: it goes the other way around. The chain runs in both directions. What we do to the water we do to ourselves, because we are mostly water. What we do to the soil ends up on our plates and inside our cells. And, just as truly, what you do for your own nature, an hour under trees, a morning beside moving water, is not separate from the health of the whole. It is you, tending your own link in the chain.

We never left

It helps to take inner nature literally for a moment, because it is literally true. Your body is close to the same fraction water as the surface of the Earth, a rhyme this site has pointed to before: roughly seventy percent each. Your sleep and waking still run on a clock set by sunrise, written long before there were clocks. And you are far less a single, sealed individual than you were taught. You are a walking ecosystem, home to trillions of microorganisms without which you could not digest a meal or hold a steady mood. There is even early evidence that ordinary bacteria living in healthy soil may nudge the brain’s own chemistry of calm, which would mean the old feeling of a garden being good for you is not entirely in your head.

The biologist E. O. Wilson gave this bond a name: biophilia, the idea that our pull toward living things is not a taste we pick up but an inheritance we are born with, written in by the long ages our survival depended on reading the living world well. It is, in a sense, the scientific name for this entire pillar.

Food is where the outer nature becomes the inner one most plainly. As our pages on food put it, food is the physical intersection where the health of the land and the health of our bodies meet. Every meal is a piece of the landscape entering the bloodstream. Grown in living soil, it arrives as nourishment. Grown in exhausted ground, something is quietly missing, in the food and, eventually, in us.

For almost the whole of our story as a species, several hundred thousand years, none of this was a philosophy. It was Tuesday. We lived outdoors, in weather and dirt and green. Only in the last two centuries, a blink, have we moved inside, and the move is nearly complete: the average American now spends about ninety percent of life indoors. The body never got the memo. It still expects the older world, and it tells us so, in a language we have half forgotten how to read.

What the body remembers

Here is the remarkable part. When we do step back into that older world, the body answers fast, and in ways we can now measure. The science is young and, in honest truth, still uneven, built from many small studies rather than a few large ones. But the direction it points is consistent, and it keeps confirming something older cultures never needed a laboratory to know.

Start with one of the oldest threads of evidence, and one of the simplest. In 1984, a researcher named Roger Ulrich pulled the records of forty-six gallbladder surgery patients in a Pennsylvania hospital. The one difference between them was the view from the bed: half looked out on a small stand of trees, half onto a brick wall. The patients with the trees went home sooner, drew fewer worried notes from their nurses, and needed fewer doses of strong painkillers. A window. That was the entire intervention. It was a small study, and an old one, but it opened a door, and a generation of research has walked through it.

The mechanism underneath is your threat system standing down. Your nervous system spends the day scanning for danger, and a cluttered, enclosed, unpredictable environment keeps that scanning switched on. Open water, a wide horizon, the ordinary green of a park: these read, at a level well below thought, as safety, as a place with nothing hiding in it that means you harm. The parasympathetic branch of the nervous system, the one in charge of rest and repair, comes forward. Heart rate settles. Cortisol, the body’s main stress hormone, falls. This is not poetry; it is plumbing. In Japan, where the practice of shinrin yoku, or forest bathing, became the subject of serious medicine, researchers led by Qing Li have documented these shifts again and again: time among trees lowers stress hormones and blood pressure and tips the whole system toward calm.

Then there is the mind going quiet, which is harder to measure, and, when someone finally managed it, more striking. In 2015, a team at Stanford led by Gregory Bratman sent volunteers on a ninety minute walk, half through a leafy corridor, half beside a roaring multilane road, and scanned their brains before and after. The nature walkers came back with measurably less rumination, that grinding loop of self critical thought that so often runs ahead of depression, and, on the scans, measurably quieter activity in the exact region of the brain that lights up when the loop is turning. The city walkers showed no such change. Same exercise, same ninety minutes. The difference was the trees.

Part of why is a matter of attention. Through a screen filled day we run on what psychologists call directed attention, the effortful, top down focus that filters distraction and forces decisions, and it tires like any muscle. Nature offers a different kind of engagement, the gentle, involuntary pull of moving water, a drifting cloud, a bird crossing the field of view. It holds our attention without demanding it, and in that soft holding the worn machinery of focus gets to rest and refill. It is why an hour outside can leave you sharper than an hour of trying to be sharp.

The body’s defenses join in, too. Trees release aromatic compounds called phytoncides into the air they share with us, and when we breathe them in, something surprising follows: the number and activity of our natural killer cells, an immune line that helps the body find and destroy damaged and cancerous cells, climbs, and stays elevated for weeks afterward. The forest, in a real and unsentimental sense, is medicating you through the air you breathe in it.

And how much of it do we actually need? The data has an answer, and it is smaller than you would fear. Studying nearly twenty thousand people, researchers found a clear threshold at about two hours a week of time in nature, above which people were consistently more likely to report good health and real wellbeing, and below which the benefit mostly disappeared. It held for the old and the young, for those with money and those without. It did not matter whether the two hours came as one long visit or a scatter of short ones. Two hours a week. A prescription, hiding in plain sight in the numbers.

There is a name, too, for the largest version of the feeling. Awe, the sense of standing small before something vast, a canyon, a night sky, a storm building out over water, appears to quiet the brain’s self referential chatter and briefly loosen the grip of the anxious, calculating self. We come back from it feeling like a part of something, rather than the harried center of everything.

Stand back from the separate findings and one shape emerges. Contact with the living world moves the body out of the state modern life keeps it stuck in, the low, constant readiness to fight or flee, and into the state where it heals, digests, sleeps, and repairs. The feeling we call peace, at the edge of the ocean or the top of a climb, is the felt side of that shift. It is not a mood that happens to visit. It is a measurable change in a nervous system that has finally been allowed to stand down.

Why the absence now has a name

Which raises the obvious and uncomfortable question. If contact with nature does all of this, what happens when it goes missing?

That absence now has a name. In 2005, the writer Richard Louv called it nature deficit disorder, in a book about children growing up sealed away from the outdoors. It is worth being precise, in the honest spirit this site tries to keep: it is not a clinical diagnosis, not an illness in any medical manual. It is a name for a pattern, and the pattern is real. It is the indoor childhood and the bright rectangle, the paved over commons, the slow shrinking of what one scientist called the extinction of experience, in which each generation grows up with a little less contact with the living world, and so expects a little less of it, and defends a little less of it. Louv went on to found the Children and Nature Network, which you will find linked on our own pages, precisely to turn this around. Think of nature deficit as a broken link in the chain we began with, felt from the inside. Naming it is the first step. The second is doing something about it.

The oldest medicine

And here the story turns hopeful, because the something is already underway, and it looks a great deal like a prescription.

In Canada, a national program called PaRx now lets licensed doctors, nurses, and other clinicians literally prescribe nature to their patients, a pass to the national parks written on the pad beside the usual advice. It carries the endorsement of the country’s medical association, and it grew out of a grassroots movement that began, more than a decade ago, with a handful of American doctors who noticed what their patients were missing. Nature is medicine, a natural companion to the food is medicine movement this site already champions. And the people building these programs frame it exactly as we do: healthier people and a healthier planet, in one motion. They say something else, too, that our pages on ancient wisdom would recognize at once, that Indigenous knowledge held human and ecological health to be a single thing long before there was a word for it. The laboratory, in the end, is catching up to the campfire.

This is the ground we intend to keep tending here: the science of what the natural world does to the human mind and body, told honestly and kept current, and the growing practice of putting that knowledge to work. Consider this page the doorway to it.

As within, so without

So here, at last, is the deeper reason this pillar stands beside the others, the reason it is not a soft addendum to the real work of protecting land and water, but part of the same argument.

We protect the coastline and the forest and the living soil not only for the planet as some distant abstraction, and not only for our children and their children, though those reasons are more than enough. We protect them because we are not separate from them. We are the part of nature that has begun to notice itself, a nervous system the Earth grew, and a wounded outer world makes for a wounded inner one, as surely as clean water makes for a clear mind. The chain runs both ways. That was the whole point of the sentence in the middle.

And it means that tending your own nature, the walk after a hard day, the morning beside moving water, the two hours a week the science quietly asks for, is not an indulgence stolen from more important things. It is one of the important things. It is you, keeping your own link in the chain well, and in the doing, remembering, in the body and not only the mind, why the whole chain is worth protecting.

Everyone carries an ideal location somewhere inside them, a place that made them who they are. That is not only a lovely idea. It is a piece of nature you are carrying with you, and it is asking, gently, to be visited.

Go.

The research behind this page

The Nature Effect

A companion series on the science of our inner nature, the growing body of research on what the natural world does to the human mind and body, told honestly and kept current. New pieces are added as they are written.