“A deep exploration of the biology and cultural dimensions of breath, the life force that sustains us all from the moment we enter the world until our departure. It is beautifully written—clear, accessible, often poetic. Dr. Stephen weaves together science, history, philosophy, religion, and clinical vignettes to present a tapestry that will engage the reader from the first page to the last.”—Jerome Groopman and Pamela Hartzband

“Surely this is exactly the right moment to appreciate and understand our lungs, and Michael Stephen’s Breath Taking is scientifically fascinating, calling our attention to the almost literally invisible processes that keep us alive, while explaining passionately and even lyrically the many complexities of lungs and breath and breathing.”—Perri Klass, MD, author of A Good Time to Be Born: How Science and Public Health Gave Children a Future

“Breath is life and breathing is a fundamental human right, one which we often take for granted. Breath Taking is an important work which explores the science of our lungs, and emphasizes the urgency for lung health not just for us as individuals, but also for our planet, our environment, and the human race.”—Mallika Chopra, author of Living With Intent and Just Breathe: Meditation, Mindfulness, Movement, and More

The emphasis on the breath is not a thing of the past for Eastern religions; breathing continues to occupy a central role in their teachings today. The Hindu name for the breath is prana, which, like the western ruach and Holy Spirit, is not just a word for air, but an acknowledgment of the breath as the ultimate life force. This knowledge is spreading back to the West through disciplines such as yoga and mindfulness, but also through techniques aimed at improving endurance, and even intimacy. These practices demonstrate that the mind and the heart follow the lungs, not the other way around.

Civilizations throughout history have equated the breath with the soul, using one term to refer to both. In ancient Egypt, it was ka; in Zulu, umoya; in ancient Greece, pneuma; in Hinduism, prana. In his 1653 Lectures on the Whole of Anatomy, William Harvey, the famous seventeenth-century British physiologist, stated simply but profoundly, “Life and respiration are complementary. There is nothing living which does not breathe nor anything breathing which does not live.”

As an organ, the lungs must do an incredible amount of work all day, every day. With an average respiratory rate of fourteen breaths per minute, and an average volume of 500 milliliters of air per breath, a typical adult inhales and exhales 420 liters of air every hour. In one day, the total is roughly 10,080 liters, a tremendous amount of gas for every human on this planet to utilize. Yet, in the absence of lung disease this work is effortlessly integrated into our lives, happening without any conscious effort.

With a signal from the brain, the diaphragm contracts downward, expanding the lungs in an instant. In this way, the breath of life is drawn into the body, and contained in it are millions of oxygen molecules. The lungs seamlessly pass the oxygen off to the red blood cells, which, with the help of the heart, deliver these molecules of life to the cells of the brain, muscle, kidneys, and other organs. Continuing the circuit, carbon dioxide, produced as oxygen is consumed by our tissues, is whisked through our veins and back to the lungs, and then expelled into the atmosphere as the diaphragm now relaxes. It is a beautiful circle of reuse and recycle, appropriately termed circulation, with the lungs as the centerpiece, the lynchpin connecting the body and the outside world.

That oxygen, life, and lungs all came into our world in relatively close succession is no coincidence. Only with oxygen and some means of extracting it are all things possible—thinking, moving, eating, speaking, and loving. Life and the breath are synonymous. Significantly, our arrival into the world as infants is considered a success when we take our first breath outside of our mother’s womb, and our leave-taking occurs when our last breath is expelled.

We are not the only ones breathing, of course. Breathing is the mechanism for harnessing the life force all over the Earth, and every organism above the level of microscopic anaerobe respires, including every single fish and animal, as well as all plants. Plants are known as oxygen producers because of photosynthesis, but they, too, constantly breathe, consuming oxygen to fuel their energy needs at the same time photosynthesis is occurring. We all utilize this communal resource called the atmosphere together.

There is something transcendent in the very structure of our respiratory system. It begins in the trachea, the single wide tube that accepts air after it comes in through the mouth or nose. The trachea branches into the bronchi of the right and left lungs, with the airways continuing to divide into increasingly smaller tubes, finally opening, deep in our lungs, into grapelike clusters called alveoli, the actual site of gas exchange. This structure, taken as a whole, resembles a tree, with its trunk and progressively smaller branches emerging into their site of gas exchange, leaves. Other examples of this configuration in nature abound—streaks of lightning converging into a single bolt only to diverge again as they approach the ground; the tributaries of a riverbed unifying into one main waterway; the human body itself, branching from its trunk to arms and legs, then fingers and toes. The lungs tap into something universal in their structure, maximizing uptake of the life force that surrounds all of us.

Science is beginning to investigate in a serious manner something humanity has known for centuries—that the breath can be used to heal the body. Every year more papers are being published on the healing power of the breath. Evidence of improvement in patients with asthma, chronic obstructive pulmonary disease, chronic pain, depression, and even cancer has been demonstrated. The scientific evidence has started to go even deeper, to the level of our blood, and even our genes. In those who practice breathing exercises, levels of inflammatory proteins in the blood are significantly lower, especially under certain types of stress. Mobilizing the power of the breath has also been shown to turn on anti-inflammatory genes and turn off pro-inflammatory ones, including genes that regulate energy metabolism, insulin secretion, and even the part of our DNA that controls longevity. Looking down the generations, those of us who practice breathing exercises today may well pass on more disease-resistant genes to our descendants tomorrow.

There is also something about the lungs—beyond their role in disease prevention—that is essential to our existence and future survival. The lungs are our youngest structure evolutionarily, having developed as our ancestors emerged from the ocean some four hundred million years ago, well after the heart and other organs had evolved. In addition to being the central organ at both birth and death, they are also the body part we must accommodate in the future if we are going to colonize other planets, or even stay alive on this one, with its radically changing climate and the constant threat of respiratory pathogens. Like our other organs, the lungs are under unconscious control of our brain, but unlike our other organs, we can control them consciously if we choose.

With this element of control, the lungs are hailed at present as an important focal point for the health and progress of society as a whole. We live in a time of extraordinary change, with technology and medicine bringing unheard-of advances in the last hundred years. Average human lifespan has recently doubled, the number of people on Earth tripled. At the same time, we have naturally held onto the same emotions of anxiety and distrust that helped us survive at a time when we faced completely different threats than we do now. For us to move forward as a people and as a planet, we are going to have to become more trusting, more cooperative. The lungs are the organ that could help us make this transition.