—photo by hilectric

It’s not easy, breathing well. I once had a singing teacher (you may remember her) who tried to show me all the ways a human body can expand to allow more room for air in its lungs. She stood with me in a loose embrace, her hands gently resting against the small of my back, and told me to try to push them away. But that’s nowhere near my lungs, I protested, hardly believing I could press my whole flesh and frame outward simply by drawing in oxygen. But it was true: given time, muscle and bone gently gave way to the swelling force of a knowing breath. I could, I learned, control to an astonishing degree the rate, depth, sound, and shape of my breathing.

What was also astonishing was how difficult it was. Not just physically, although training half-forgotten parts of my body to stretch and contract on command was tiring enough. Equally laborious was the mental effort. I had to consciously take charge of a process that, given the slightest excuse, my brain would simply take over. During exercises, focusing on the fact of my breathing alone, I’d become a champion of deep, slow inhales and strong, steady exhales. But as soon as I started to sing, my mastery fell away. Unless I paid perfect attention to the feel of the air flowing through my lungs, I’d wind up running out of it.

Sucking in ragged breaths at the end of a note, all became clear. It was a dance I was in. My brain and I had to take it in turns to grasp and cede control over the rhythmic steps of my breathing—and I was not at all used to leading.

But how exactly does the brain lead this dance? What process is responsible for perpetuating the simple, indispensable pattern of muscle movements that persists from first breath to last?

The fact that breathing is necessary to sustain life is plain. The fact that the brain controls breathing is somewhat less plain (the Greco-Roman physician Galen was one of the first scientists to realize this, after noticing that respiration—among other things, one would imagine—suddenly ceased in an unfortunate gladiator whose brain stem had been severed from his spinal cord).

The actual mechanisms by which the brain controls breathing are delicate, complex, and not at all obvious. Until quite recently, for instance, neurobiologists believed that a single center in the brain was responsible for directing the intake and outflow of breath. A few years ago, however, it became clear that at least two networks of cells, both located in the brain stem, are involved.

One system, known as the pre-Botzinger complex, appears to adapt the rhythm of breathing to adjust for internal and external environmental factors. Our breathing can change, after all, in an instant—the sweet, deep hypnagogic breaths of drifting into dreams after a long day’s work racing without pause into the sharp, shallow gasps of what was that sound that just broke the night? The second system, made up of cells known as pre-I (for pre-inhalation) neurons, has been called breath’s pacemaker. It, scientists think, works to tug the rhythm of our breathing back to its regular rate—ensuring that it remains, above all, steady, stable, and unfaltering.

Apart from the times in which we (struggling to calm a nervous heart or maintain a state of meditative bliss) seize conscious control over our respiratory systems, these two cellular networks in our brains seem to be involved in their own elaborate dance of give and take—balancing the incredible responsiveness of our breathing with its unfailing reliability.

Or almost entirely unfailing. German folklorists tell the tale of a water nymph named Ondine, as beautiful and lithe a creature as any mermaid ever was. Unfortunately for Ondine, she falls in love with a human; her lover Hans is as fickle and inconstant a creature as any mortal man ever was. When he leaves her for another lover, Ondine’s father—king of the sea and possessed of both power and cruelty in equal measure—curses her capricious paramour. Since once he swore to be faithful to Ondine with his every waking breath, Hans is now doomed to lose his breath forever the very moment he falls asleep.

“Ondine’s curse” is what the medical literature prettily calls congenital central hypoventilation sundrome, a rare genetic disorder that affects the autonomic nervous system in such a way as to cause the failure of automatic breathing. Children born with CCHS breathe normally when they are awake, but often “forget” to do so once they enter quiet sleep, and most can only hope for long-term survival if they undergo tracheotomies that allow them to be hooked up to ventilators at night. CCHS brains are quite literally unable to take over control of the body’s inhalations and exhalations; these children have lost a partner in their constant dance.

Having read about Ondine’s curse, I can’t help thinking about it sometimes, in the drowsy, comforting minutes before I fall asleep at night. As I feel my chest rise lightly, fall gently, under my own volition, I am suddenly struck by how soon I must let go of all my intention. And I try, paradoxically, to stay awake while I lose consciousness. More than anything, more than the fear of stillness, I long to trace that silent passing of the baton from my conscious self to my involuntary brain. I long to know the impossible: what it feels like to be at once awake in my body and in the grip of an ancient will that is all my own and yet, after all, does not belong to me.