Once there was a time when the heart meant everything. It was the engine that kept us alive, the emotional seat of the soul, the repository for, and projector of, everything and anything to do with love. But we all know now that the brain is where the real action -- and feeling -- is, while the heart is just a four-chambered muscle, a relatively straightforward pair of pumps contracting in sequence to push deoxygenated blood into the lungs and oxygenated blood out into the rest of the body.
Despite this scientific certitude, we have yet to figure out how to make an artificial heart that works a fraction as well as the one we're born with. (The most successful artificial heart -- the Jarvik 7 implanted in Barney Clark in 1982 -- only kept its recipient alive for a few months.) And even though we've known for quite a while exactly what our blood is made up of, researchers are still struggling to discover a truly workable blood substitute.
All of this may be discouraging to researchers and to those who suffer from heart ailments, but it also may, somewhat perversely, be rather encouraging to the poetically inclined. For them, and for all of us, it may not be too late to claim that love and the heart have more in common than our brains might like us to think.
Take, for example, the recent work of cardiologist Ary Goldberger of Harvard and Boston University physicist Chung-Kang Peng. Studying healthy volunteers and those suffering from advanced heart disease, they discovered that the time interval between heartbeats fluctuates dramatically, even when a body is at rest. Healthy hearts seem to have a built-in mechanism that keeps the fluctuations within a certain range; if the last 300 beats were slightly faster than normal, the heart beats slightly slower than normal for the next 300. Goldberger and Peng called these fluctuations "long-range anti-correlations."
Heart disease, Goldberger and Peng discovered, weakens the heart's "memory" -- it "forgets" to compensate, and can settle into a lengthy run of beats far from the norm. Imagine crossing a river on the curved surface of a fallen tree. You can zig and zag from side to side and remain balanced, but get stuck favoring only one side of the curve and you are much more likely to end up wet. The unhealthy heart zigs, it seems, more than it zags.
Also quite revealing was a paper published in Nature two months ago that claimed that changes in interval fluctuations were not random but operating according to the deterministic logic of chaos theory. Chaos differs from randomness in that, while long-term outcomes and heartbeat patterns are unpredictable, the timing of each individual beat is influenced to some extent by the timing of the last few.
What researchers Chi-Sang Poon and Christopher Merrill of the Harvard-MIT Division of Health Sciences and Technology discovered is that heart disease actually makes the beats less "chaotic," meaning that disease is not a slippage into disorder but, almost paradoxically, a trend toward order and regularity. Like a tennis player waiting for a serve, the heart is better off wobbling on its toes than standing pat, albeit flat-footed.
What consolation to all of those who have described their love life as "utter chaos" to know that they might have been scientifically accurate! Love is a classically chaotic system with its ups and downs, its fast beats and slow, its short-term predictability and long-term mystery. It reveals signs of mathematical complexity in the unintended consequences small actions can have.
When love works, the person in love easily convulses with the electric charge of another, reinvigorating a past, working to create a shared life relished for the fact that it is, within a tolerable range, unpredictable. On the other hand, when memory weakens, when lovers forget where they've been and where they need to be heading, when things get too predictable, relationships wither; a dampness seeps into the bones.
Predictability, or "bad memory," as scientists have found, may simply be symptoms of familiar heart ailments, like
coronary blockage. But even in such cloggings metaphorical parallels abound. As Shakespeare put it, 318 years before American physician James B. Herrick first described hardening of the
arteries, "Sorrow concealed, like an oven stopp'd/Doth burn the heart to cinders where it is."
Of course it takes more than muscle contraction and clear passageways to keep a person alive. It takes blood; and
here, too, physiology mirrors metaphor. Proust once remarked that
love is composed of an infinity of successive loves, "each of which is ephemeral although by uninterrupted multiplicity they give us the
impression of continuity, the illusion of unity." So too blood, which in a cubic centimeter contains no less than 4.5 million to 5.5 million red blood cells (erythrocytes), 150,000 to 400,000 platelets and 7,000 to 12,000 white blood cells (leukocytes).
If love is in part a state that transforms that which
moves through it, then for us it is each event in a relationship that finds its counterpart in the millions of blood cells rushing through our hearts -- cells that by all non-magnified appearances give the appearance of continuity and unity. Love, like our leukocytes, protects us from sickness and disease. Love, like our platelets, helps us to stop the bleeding. And love, like our erythrocytes, helps us to breathe.
With the help of the heart, blood transports the nutrients that keep us alive, gets rid of our metabolic waste products, helps us absorb oxygen and remove carbon dioxide and helps us regulate our hormones. Stated in slightly less scientific
terms, this might be a description of a wonderful relationship. It seems that whether we look at the heart itself, the job it does or the stuff it transforms, we see glimpses of love among the plasma.
Of course, knowing that our hearts are complicated, chaotic things might not make Valentine's Day any better; the heart and love may, in the end, have nothing more in common besides the fact that their inner workings remain a mystery. While it has been
possible for 30 years to transplant a healthy human heart into another person, no such recourse exists for the emotionally broken-hearted.
But how apt that it is now science, not folk tales, reminding us that we are of the heart, and we are like it, too; that in a modern world it takes mathematics and biochemistry to hint at what tradition always insisted: The heart may be a simple thing, but only in the same sense that the word "love" is one of the
shortest in the English language.