(Sample chapter excerpted from the new book, "Change Your Body, Change the World: Reflections on Health and the Human Predicament." Available here.)

It may well be that more and more of what people bring before doctors and therapists for treatment—agonies of body and spirit—are symptoms of the biospheric emergency registering at the most intimate levels of life. The Earth hurts, and we hurt with it.

Theodore Roszak The Voice of the Earth

The year was 1962, the setting a small alpine valley near Lake Tahoe in the Sierra Nevada Mountains of California. I was but a young creature, a curious mammal of no particular distinction. It was a glorious summer day and my first real exposure to an alpine habitat. Our family was camped beside the Carson River and for the first time, I was cut loose to explore the banks of a nearly pristine mountain stream.

My mother kept a vigilant watch as I scrambled up, down and along the stream bank. I soon discovered the boulders—gorgeous granite blocks that were both smooth and rough, clean and inviting. As I climbed and scrambled, I had the most powerful realization of my young life, a personal Zen moment that has stayed with me for almost 50 years.

At first contact with the granite, I was overcome with pleasure as my hands, feet and knees touched the gorgeous orbs. I was instantly delighted with a profound sense of exuberance—astonished that something could feel so good and so right for my body. My muscles rejoiced; these shapes were perfect for pushing, pulling, climbing and jumping. It was like the playground at my elementary school, only a thousand times better. It struck me as a wonderful coincidence: these boulders, this river—this world—was made just for me, for my body. Or, I was made for it. But no matter; every detail of the outer world seemed a ideal match with every detail of my anatomy and physiology. My joy was boundless; I belonged to this place. My body, mind and spirit were happy.

Not surprisingly, the boulders continued to draw me back, even after my family returned home to what would later be called Silicon Valley. As my body matured, I returned to the Sierras at every opportunity and touched the alpine habitat in every way possible: hiking, scrambling and climbing the walls in Yosemite. I loved the granitic world and it loved me back. My body became strong and my spirit soared.

But sadly, the joy of my first alpine contact was later eclipsed by an equal and opposite experience, a toxic event that has repeated itself thousands of times over my adult life. This time I was stuck in traffic somewhere south of Oakland, boxed in by a pod of monstrous 18-wheelers, incarcerated in a cage of sheet metal, glass and plastic. The summertime heat was intense and the exhaust savaged my lungs and eyes. All I could see were cars, trucks, concrete retaining walls and outdoor advertising—no plants, no animals, no color, no texture. Not only was my world lifeless, noisy and hostile, I was utterly powerless to change it or escape. Stress hormones flooded my bloodstream and my spirit raged.

I sought refuge in the radio, but all I could hear were annoying advertisements and yet more noise. As I fought back against my predicament, a voice rose up through the stress of my frantic consciousness: “My body is not made for this! This place is not made for my body.” My tissue screamed, “This is profoundly, fundamentally wrong. It is wrong by a million years. It is a mismatch for every cell of my being; I hate it and I am right to hate it.”

Unfortunately, there have been many such instances of environmental mismatch in my adult life, days in which the moments of distress and alienation far outnumber the Zen moments of perfect fit. Increasingly, as modernity grows ever more tyrannical, my sense of psychophysical alienation grows as well.

This experience is much more than my own neurotic drama, however. My sense of mismatch is now shared by an increasing number of people around the world. We may not put it precisely in these terms, but our bodies know the truth: our modern world is an increasingly unfriendly and alien place. Something is drastically, spectacularly wrong with the world that we have created.

For some, this connection between personal and environmental health is an abstraction; they see no association between a sick biosphere and a sick body. They feel terrible, but can’t say why. They see no relationship between the pain in their bodies and the accelerating destruction of habitat around the world. Others are more sensitive to large-scale planetary influences. Dave Foreman, founder of Earth First!, describes his experience this way:

I am an animal! A living being of flesh and blood, storm and fury. The oceans of the Earth course through my veins, the winds of the sky fill my lungs, the very bedrock of the planet makes my bones. I am alive! When a chain saw slices into the heartwood of a two-thousand year old Coast Redwood, it’s slicing into my guts. When a bulldozer rips through the Amazon rain forest, it’s ripping into my side. When a Japanese whaler fires an exploding harpoon into a great whale, my heart is blown to smithereens. I am the land, the land is me.

This is not just the poetic raving of a frustrated activist. Say what you will about Dave Foreman and his utopian band of Earth First! eco-criminals, I have no question that Mr. Foreman literally feels these things in his body. I also have no question that these events are likely to have adverse effects on his health and our health as well.

Over the last several decades, many people have had experiences similar to Dave Foreman’s and my own. Many of us have felt the extreme physical distress of the body–environment mismatch. Locked in climate-controlled buildings, working around the clock, stuck in cars, eating food-like substances of unknowable origins, living in ambiguous networks of constantly shifting alliances, our bodies begin to squirm, our teeth begin to grind and our spirits suffer. Disease creeps into our tissue.

We write off our anxiety in various ways. Perhaps it is our fault for being unhappy in this modern world. Perhaps we are maladjusted; maybe we need psychotherapy or medication. Perhaps a doctor can help us feel better. Maybe some alternative methods will get us back on track. Maybe we just need to train harder and push through the adversity.

But increasingly, many of us are beginning to realize that, in one sense, it’s not our fault at all. We feel an incredible sense of physical and psychological angst, not because there’s anything wrong with us, but because there is something profoundly wrong with the world we have created for ourselves. We are OK; it’s our human-engineered environment that’s killing us.

If you’ve been suffering this deep primal angst, this sense of environmental–existential pathology, you are not alone. In fact, your suspicions are now being validated by scientists across the spectrum. Paleontologists, evolutionary biologists, physicians, psychologists, zoologists and animal behavior specialists are all beginning to see our predicament with greater clarity. All animals, including humans, do best in their native environment. Change that environment drastically—as we have done—and you’re bound to see distress. It doesn’t matter whether you’re fish or fowl, buffalo or biped: life in a mismatched habitat is bound to be difficult for flesh and for spirit.

The good news is that the body is set to make a comeback, and not a moment too soon. For centuries the human body has been locked up in a Cartesian prison, stifled by a Puritan-Victorian value system, punished by workaholism, pushed off the land and isolated from the natural world. We’ve disempowered ourselves by putting our bodies into the hands of a professional expert class. We’ve medicalized every dimension of physical living: birth, exercise, food and death. We’ve professionalized youth sports and taken away recess for both children and adults. The body has been incarcerated by its own hand and is now beginning to suffer the consequences in epidemic levels of psychophysical disease and unhappiness: obesity, heart disease, diabetes, depression and physical apathy.

But there’s a change in the air and on the ground. The body’s comeback is being driven by discoveries in neuroscience and social psychology that prove beyond question that the body is deeply and intimately involved at every level of human experience. These discoveries tell us something that is at once ridiculously obvious and profoundly counter-cultural: the body is essential to our lives. Its health is crucially important to the vitality and function of the brain, to social cohesion, creativity, decision-making and in turn, to prosperity and a sustainable human future. It has now become clear that our conventional “brain on a stick” approach to education, management and living is outmoded, ineffective and extremely dangerous.

It’s time for the body to get back into the act.