I’ve been going to bed alone this summer while Ross is in England, and the nights are hot and still. As the day ceases to stir and I grow deaf to the low drone of the fan, the spaces between sounds spread till they touch, silence to silence. No other body breathes; no other arms shift raspily against sheets. Sometimes I find it hard to sleep in the hush. But then I turn to rest my ear against the pillow, and I am not alone. The rhythm that has inhabited my body without fuss or fanfare all through the day makes itself known: my heartbeat.
As it does I am engulfed by a sensation of amazing intimacy and fascination. I don’t control my heartbeat. Like perspiration, salivation, digestion and the dilation of the pupils, the beating of the heart is a process that falls under the control of the autonomic nervous system, and is largely involuntary. Yet it feels in this moment as if I can magic it into and out of existence—lift my head and it disappears; lay it down and it returns. It seems what it is not: ephemeral.
The thump itself, when I rest my head, is familiar. Primeval. It’s a version of the maternal rhythm I must have heard as soon as my newly forming ears began transmitting signals to my newly forming brain, weeks after conception and not long after my own primitive heart hiccuped into being.
(Before the heart becomes a servant to the rest of the body, it may beat for its own sake. The first contractions and expansions of the heart, some scientists think, are not required for the diffusion of nutrients and respiratory gases throughout the developing fetus. Instead they trigger the formation, shaping, and growth of new cardiac muscle and the tiny blood vessels that are starting to finger out from the heart. In other words, every heartbeat begins as a self-fulfilling prophecy.)
This beat I hear now, though, is distinctly mine: made by the specific mechanical properties of my muscles, bone, and blood. And no one else can experience it in quite this way: no doctor channel it through a stethoscope, no lover rest an ear to my chest and capture the same immersive resonance. Having my heartbeat in my ear is like listening in on a secret conversation, my body speaking to itself.
Structurally, the heart is a beautiful thing, designed for one thing and one thing only: to pump. It has two muscular halves, each of which is divided again to form an upper atrium and a lower ventricle. A heartbeat may sound simple, but it’s only the barest glimpse of the complex, precise, and exquisitely coordinated choreography of blood into and out of these four chambers.
First, the upper chambers of the heart contract: the muscle twisting and tightening like the fabric of a dish rag being wrung dry. This squeezes blood from the atria into the ventricles, which relax to receive their cargo. Next, a complementary event: the atria relax and the ventricles contract, squeezing blood into the arteries (blood from the right ventricle travels to the lungs to pick up oxygen; blood from the left ventricle travels out into the body to deliver it).
Most of this movement is silent to me, except for the opening and closing of the heart valves—each a set of two or three half-moon-shaped flaps that direct the flow of blood into and out of the organ. They are responsible for the beat repeating in my ears as the whole astounding process takes place, over and over, in the still of the night. Lub and the tricuspid and mitral valves pull shut behind the blood that’s just pumped into the ventricles; dub and the aortic and pulmonary valves do the same after the blood that’s just pumped into the arteries. Lub dub, lub dub, lub dub: such a sweet, optimistic sound.
I think what makes the thing seem loveliest of all is the deep choreography behind it. A heartbeat is all about the careful management of the balance between contradictory states: open, closed; expanding, contracting; inwards, outwards; full, empty; oxygenated, deoxygenated; at work, at rest. And out of the unceasing transition between these states, we get steadiness. It’s practically a Zen koan written into physiology—a most muscular teaching.
The reason this koan rushes through my ears when I place my head against my pillow? For that I can thank the internal carotid arteries that ribbon up each side of my face. On their way to the brain, these arteries pass right in front of the tympanic cavity: that inner cave of the ear where three tiny bones are curled, their only job to vibrate in response to waves of pressure and begin converting them into what I perceive as sound. It is not my heart itself I sense throbbing in my ears, but a kind of echo, as dipping your hand into a fast-moving river you feel the push of a wave that originated many miles upstream.
This past Thursday in the bird lab, I heard—or rather, saw—another echo. After one clumsy move with a scalpel, I opened a cut the length of an eyelash on the skin of my left index finger. There was a moment of what seemed like stunned affront on the part of my cells—and then I bled. Swaddling a band-aid around my finger, pressing vein against bone, I felt my pulse grow tight and insistent. I held my finger up to stare. The vessel I’d cut into was quite a long way downstream from the heart, but blood was still being propelled through it with enough force that if I looked closely I could see the shape of each echoed beat, thrusting against the flimsy fabric barrier I’d put up around my wound.
It was almost as if my heart had doubled: sent a second, smaller, version of itself to the precise location of the insult I’d created. The finger ached a little, but I smiled. To be cut, bruised, hurt, I understood, is to be aware of the heart’s extraordinary compass. There is no place in the body to which its drumbeat does not carry; no tissue it cannot touch.
Every squeeze of a healthy, reaching heart drives about three ounces of blood through its chambers (as much of the stuff as you could carry onto an airplane in a single plastic container, if you were so inclined) and fifty times that volume through the body as a whole. So much power lies behind the heart’s contractions that in the space of one minute a single red blood cell, pushed along on the tidal wave that begins in the heart, can whiz through an average of three full laps around the circulatory system—journeying each time from heart to lungs to heart to oxygen-hungry cells, and back again.
This is a fabulous statistic, so to try to get inside it I start walking and count to twenty, the time it takes for one such round. No fucking way. It’s hardly long enough to get from the kitchen to the living room window. And in that time, I am supposed to believe, trillions of blood cells have completely traversed the length of what is, for them, the entire universe? Driven by this crazy heart of mine?
It is fierce, this muscle. With a strong heart on your side, nothing seems impossible. You might run 10,000 meters in under 30 minutes. Dive the height of a skyscraper on a single one of your own breaths. Me? I don’t reach that far. But I’ll tell you that I’ve been working with my heart at the gym for three years, and I can now run for a bus without sending it into palpitations. Some of us will take what support we can get.
Some don’t believe their hearts are on their sides at all. Another word for steady is inexorable, and the phrase keeping time has a dark second half—until it runs out. Something wild and fearful lies just on the other side of the calm thrumming that keeps me company when I’m in bed. The other day I read the following plea for help on a mental health forum.
I’m terrified of my heartbeat. I hate that my life is controlled by my heart. It’s a small muscle and it’s so powerful. It’s in control, I am not. I hate it.
I wish somebody could snap me out of this horrific phobia. I can’t stop thinking about it because it’s always there, always beating.
I get happy and then I stop, remembering I have a heartbeat, I’m human, and if I’m alive and not here to live a crazy life, I’m just here to be a mammal, because I have a heartbeat. I’m not here to have a job, or love…I’m here to eat, survive, reproduce and die.
It’s horrible. I hate having it. I wish somebody could convince me my heart is my friend and not my enemy.
There is part of me that understands this terror.
I imagine a stranger offering to put a metronome inside me that would tick off the moments remaining in my finite existence, beat by beat. I would, they’d explain, be able to feel and sometimes hear—but not very well control—the cadence of this morbid little clock. It would feed my body and give it breath, but could itself be damaged, and when it finally ran down, so (most likely) would I. As life rests on it, so a heartbeat can be an uncomfortable reminder of our own mortality: making it ideal for starring roles in horror stories, and lending creatures that echo its modus operandi a shivery air.
There is part of me that understands this terror; but I don’t feel it.
In all these nights I have been, more than anything, comforted by the constancy—the mad beautiful stubbornness—of my heartbeat. Its metric varies from time to time, but the basic pattern it follows was set in motion in the womb, and continues, careless of my will. This fidelity of purpose amazes me; no wonder we say truehearted when we mean loyal. In my breast I carry a soldier who received a single order 31 years ago and has never once faltered.
Listen: On the strength of that order, in the space of one day the human heart beats approximately one hundred thousand times. One hundred thousand.
I find this figure frankly insupportable, and I’ll tell you why. It means, you see, that since Ross left the country mine has pulsed no less than four and one half million times. And how this is possible I can barely comprehend.
Without him here I have been left bereft of order, customs, habits. I don’t mind being on my own, but after years of learning to match the tempo of another person’s life this sudden solitude feels a little strange. The everyday beat that drives my world—the one I didn’t even realize was there—has bounced all out of time and now seems to syncopate beyond recognition. Each morning for the past six weeks I have woken and started over, trying to reestablish it.
Yet somehow in the same period my heart has stuck to its plan—followed its single basic order, in the face of the confusion I have felt. It has beat, same as always, four and one half million times. It has not asked for my permission. It has not needed my participation. It has simply proceeded, knowing exactly what it ought to do, in a way that I have not.
So I keep my head against my pillow, just a while, as darkness falls on each of these summer nights. The larger rhythm of my life may be a little hard to hear right now, but the one I hold within doesn’t seem to be skipping a beat.