The heart does not pump blood through the body.
Yes, contact with this statement may well make one recoil with incredulity, cease cognition, and run off with the urge to do some cardio exercise. One may want to withhold judgement though, since it a sign of wisdom to be able to hold in consideration two opposing ideas at the same time, including ideas one may not agree with. Hopefully, when such consideration ends, it’s not just a seed of doubt but something of value that settles in alongside the existing entrenched belief.
Leaving in place for now what is widely accepted, that the heart is a pump, let’s consider some additional facts. They may help loosen the soil for the seed to be planted.
Blood vessels in the average human span 100,000 miles, enough to circle the earth three times. The tiniest vessels are 2 micrometers wide, much narrower than the 7-8 micrometers of the Red Blood Cells, which deform and elongate to squeeze through the capillaries, one at a time. Let’s ask what intuition might say here – preferably as one sucks hard on a straw to pull a clump of tapioca balls from the bottom of a Boba tea. Could a 350 gram, fist-sized pump, with walls as thin as 5 mm, generate enough pressure to push lots of sticky fluid and cells through 100,000 miles of circulatory plumbing much narrower than the cells themselves, without bursting? Over a lifetime, the volume of blood passing through the heart is roughly 400 million liters, enough to fill a good sized lake. If a pump is indeed responsible for this, it is a pretty darn special pump.
The fill rate of the heart (looking at the venous side) is the same as the outflow rate (on the arterial side). If it is a pump, it appears as if someone inserted this pump in the middle of an already flowing river. What kind of idiot does that kind of thing? Furthermore, artificially overclocking the heart – making it beat faster by means of electrical stimulation – strangely does not increase cardiac output. The heart beats faster if the body demands it, but it doesn’t work the other way around. Blood won’t go faster just by making the heart go faster.
It is a curious phenomenon that blood flow rates are highly variable when the heart is bypassed with an aortic cross-clamp during surgery. When the outflow of the heart is completely separated from systemic circulation, blood flow may decrease, stay the same, or increase by up to 25% (depending, one supposes, on what the body decides is best for the situation). In other words, sometimes blood moves faster when the heart is out of the picture.
The normal ejection fraction of the heart, which is the portion of the blood that is squeezed out with every pumping cycle, is around ~50% or so. This is far worse than a well-designed mechanical pump can achieve. Furthermore, the ratio of external work done to oxygen consumed places its energy efficiency in the 10-15% range. These aren’t signs of a terribly efficient pump, considering that nature has had hundreds of millions of years of evolution over which to converge on doing a much better job.
As early as the 1960s, meticulous experiments on dogs by Polish surgeon Leon Manteuffel-Szoege found that blood continued to move for up to two hours after the heart was artificially stopped. Writing about the mechanical function of the heart, he ultimately concluded that blood had its own motor energy. In his words, the blood moves on its own, and the heart is in the way, slowing things down.
Finally, consider the body’s own deeply felt perception, which may quite possibly be at odds with the standard medical textbook perspective. The heart often feels like it is in the way when one is doing strenuous exercise. It appears to have a mind of its own. In contrast with legs that are ready to march up a hill or begin running on moment’s notice, the heart behaves like a sluggish teenager resentful of being roused too early in the morning. Rather than being the thing that initiates the flow of blood, it thumps along reluctantly to play catch up with a train of blood that is already flowing fast. Indeed, during intense aerobic exercise like running sprints, or heavy anaerobic exercise such as weighted squats, the large slabs of muscle in the thighs and calves are generating so much power to squeeze blood through one-way valves in the veins that the thin-walled heart barely matters. Experiments confirm that cardiac output during maximal effort far exceeds the theoretical pumping capacity of the heart, and what drives the metabolic demand and supply of the blood is the motion of the large muscles.
Facts such as these and countless other facts expose the heart’s incompetence and failure at the task that is supposedly its very reason for existence, its starring role, being a pump for the blood. Unless its role isn’t to push blood around at all. Okay, but wait, how exactly does the blood move then? Perhaps an analogy is helpful here.
Consider a tall tree. Sap flows to the highest branches with ease. Yet trees contain no heart-like pumps anywhere in their body. Roots can push water inside themselves based on osmosis, but not force it all the way up the stem in tall tubes made of dead xylem cells. Indeed, the water in the middle of a tree is a column of fluid under tension, that is, negative pressure. How does water uptake happen in trees? If you’ve heard or read somewhere that water rises up in a tree because it evaporates from the top leaves and creates suction to pull it up, this is a gross oversimplification, to the point of being mostly wrong. Trees can reach heights of 100 meters or more. Atmospheric pressures and the laws of physics dictate that a column of water in a capillary passively being sucked upwards by a vacuum can only rise 10 meters before it breaks and falls back down, which would create air gaps and be the death of a tall and thirsty tree. There are a variety of complex and active processes at play in water transport in trees, and some aspects are still not fully understood. What is known is that the water in trees isn’t like the water flowing in a tap, but rather it exists in a gel-like state known as a hydrogel. This is the fourth phase of water, with molecules arranged in a regular planar structure, which is formed when the water molecules acquire and hold a charge due to the application of energy such as the radiant energy of the sun. A slight chemical or voltage gradient can then easily transport the hydrogel, like a superconducting train floating over magnetic rails and moving nearly free of any resistance.
Look ma, no hearts
Our blood is mostly water, both inside the blood cells and the plasma outside them. Blood is also an organ. At 5 liters or roughly 10 lbs, it is by far the largest organ in the body. This organ happens to be mobile, which really makes it a slippery concept, since modern reductionist thinking in medicine has a bias towards studying and then ascribing purpose and function to what can be dissected, cut out, and clearly labeled as a body part. The inner surface of blood vessels carry a charge that in turn charges the water of blood into a hydrogel, similar to how water in sap exists as a hydrogel. This hydrogel transports itself through the largest and the tiniest blood vessels without encountering the turbulence or viscosity that ordinary water would. Endothelial cells trade oxygen and energy with the blood cells and contribute to the smooth conduction of circulatory fluid. Every tiniest part of blood moves, not solely by itself, but in interaction with its local environment on the inner surface of blood vessels.
This is known as the biologic model of circulation. Indeed, the idea that blood may be responsible for its own circulation is not a new one. Most ancients held a belief in the motive power of blood itself. In traditional Chinese medicine or the Indian system of Ayurveda, all bodily fluids including blood were bestowed with a certain life energy. This is an idea that was summarily dismissed as vitalism when Western medicine reduced the body into its constituent parts in trying to understand the whole. In modern terms, any contribution from blood to moving itself is still ascribed to “capillary power” of the vessels, as opposed to the “motor power” of a pump heart. There is a strong resistance and hesitation to ascribe any agency to a fluid itself, because honestly, that’s just freaky. In the Western conception of the world, things move only because they get pushed around. Anything else calls to mind Hollywood horror movies with names like The Thing or The Stuff or such that feature animated, mobile, self-replicating goo.
In contrast to the biologic model, the prevalent propulsion pump model, in which the heart is a dual pump pushing blood through the pulmonary and system circuits, is a relatively recent idea. It originated and solidified with the industrial revolution, and perhaps it is no coincidence that mechanical pumps played a key role in that revolution. We tend to describe nature in terms of the latest technological frameworks in fashion. The brain was variously described as a system of plumbing ducts during the pre-industrial age, as a telephone switchboard in early twentieth century, as complicated organic version of electronic circuitry later in the century, and finally today, it is spoken of as a sort of advanced computer running many software programs in parallel. All these models are just that, and fail when the limitations of taking the model too seriously are exposed. Yet, the strength of analogies is such that they become firmly entrenched in the collective subconscious. Anyone who challenges the idea that the heart pumps blood is looked at strangely. An entire multi-billion dollar industry relies on and helps sustain the models, since questioning it would question the explanations used to justify the theoretical validity of treatments such as stents and balloon angioplasty, even when experimental data show these interventions to be ineffective over the long term.
In the propulsion pump model, blood is mostly inert, a sticky fluid gunk with cells pushed along thanklessly through an infinite web of narrow capillaries by a poor straining heart. The arteries and veins are just pipes that may dilate or contract here and there but mostly just hold the blood in place. Circulation in this model has a sole contributor and single point of failure, the heart. In the biological model, blood is an organ, alive, and works together in collaboration with the heart, arteries, veins and everything else in the body to circulate itself effortlessly. Even the tiniest capillary in the system contributes to flow within, so there is no need to force anything through it. Circulation in this model has many collaborators working together to keep the system running smoothly over nearly a century, over which large parts of the heart suffer quite a bit of damage and get patched up but circulation still works. Which model sounds like something nature would evolve?
The question remains though, if the heart doesn’t pump blood, what else might it be responsible for. Why is it so critical for life? Let’s start with what it does. Researchers such as Branko Furst, building on ancient intuitions that were first articulated into words by Rudolf Steiner, have proposed that the heart actually exists to rhythmically interrupt the flow of blood already in motion. In other words, it functions as an impedance pump, not a propulsion pump. If we’re going to use silly industrial-age analogies for the heart, let’s at least compare it to the right kind of pump. Impedance, not Propulsion. Rhythmically pausing blood, not heroically pushing it. Going with the flow, not straining to make flow. Its action is like that of a hydraulic water ram, originally invented by farmers who would insert the device into an already flowing river to raise water to a higher level. A hydraulic ram is a passive mechanism that works without relying on any external power source other than the flow of the river itself. In the blood circuit, with the inlet valves open but outflow valves closed, the heart periodically impedes blood flow like a dam on a river to build up some elastic pressure (converting kinetic energy into potential energy), and then ejects the blood out with force when the pressure exceeds a threshold and pushes the outflow valves open. The periodic impedance and release of blood in two separate ejection events creates the characteristic lub-dub beat.
It is no coincidence that the heart and the lungs are situated next to each other. The heart vortexes elegantly to mix and saturate the blood with oxygen. A dynamic tension exists between the lung, as supplier of oxygen, and the peripheral tissues, as consumers of oxygen. Red Blood Cells both deliver oxygen to the tissues, as well as use the oxygen gradient as guide rails to pull themselves along, powered by a charge applied by the capillaries at every point along the way. The oxygen disequilibrium is bridged by the flow of blood, a fluid organ that picks up more oxygen than it needs and then circulates between the two extremes to drop some off. This is analogous to how sap in trees relies on charge separation powered by sunlight to pull itself up a tree towards oxygen in the leaves. In this context, the heart is an organ that impedes blood flow to maintain the balance between the pulmonary and systemic circulation, especially when the system demands a lot of blood and tries to flow it too fast. If trees were creatures with legs and limbs that ran around huffing and puffing to create highly variable metabolic demands, they’d need a heart too to keep things in order. Nobody would mistake that tree heart though as being responsible for sending tons of water hundreds of feet up.
If we’re going to use silly industrial analogies for the heart, let’s compare it to the right kind of pump. Impedance, not Propulsion. Pausing, not pushing blood.
The greatest failing of the medical heart model is exposed in the realm of human emotions. Everybody experiences some form of heartbreak in their lifetimes. That the impact is felt directly at the level of the heart, as if one has been delivered a blow or even stabbed right there, is no exaggeration. Heartbreak can literally kill. The intense agony of severe heartbreak is so universal a phenomenon that it needs to be explained by prevailing models. And it is telling that until the 1990s (that’s right, it took that long for the establishment to even wake up to the timeless experience of heartbreak), there was no medical description or even acknowledgement of it. Broken Heart Syndrome is today fancifully described as Takotsubo cardiomyopathy, after a Japanese cardiovascular specialist discovered it and compared the distorted heart to the shape of octopus traps. It is a sudden and temporary loss of the muscle tone of the heart that follows after a significant life stressor. The heart distends like a flimsy balloon, purely as a result of the emotional stimulus. It is almost as if when the organism temporarily loses interest in living, the heart sympathetically goes into a deep depression as well and refuses to get on stage. The pathophysiology is still “not well understood”, which is another way of saying that a conception of the heart as the emotional center of the body is underdeveloped in the medical science of today. All we have are vague circular arguments about the heart being affected by the stress hormones that result from an emotionally distressed mind. Cognitive dissonance runs deep in denying the heart its fundamental role as an organ of emotional processing.
Culture, whether ancient or pop, has no such embarrassing gaps in proclaiming what the heart really is. Across time, across languages, across literature, across religions, across civilizations, the heart has been invoked for all matters of… the heart. Invariably, big-hearted means generous, open-hearted means loving, and strong-hearted means brave. It is the seat of inmost feelings, it is the seat of emotions, especially love and affection, and it is the seat of courage. It is the universal symbol and primary place of residence of an organism’s soul. It is the primordial source that all seek to connect with. Every song on the radio is talking about the ups and downs of the emotional heart, and it is the subject central to every myth, every book, every movie, every interpersonal drama. It flutters in anticipation of the slightest sign of love from the object of desire, it aches when love goes unrequited, it leaps with joy when love is matched, and it hurts for lost love. When two lovers lie close together, their hearts beat together in a unified field that feels so much like one beating to be more than mere metaphor. To lay one’s head over another’s chest and immediately be arrested by the sound, for the beautiful crime of trespassing too close to another’s soul, is a recognition of the heart as the essence of a human being. It is the only organ that one can always hear and feel as alive. It is meant to be heard, the heart. Perhaps that is one reason the heart beats. It is in the business of being heard.
Yet, heartbeats are a silent phenomenon to our own ears at most times, except when we work ourselves up to a frenzy or lay on a pillow in the quiet of night. Who else might hear the pulsing, aside from the occasional ear of a lover or a medical professional? Who else is listening? How about the body itself? The heart is the epicenter of the shared inner rhythm to which we all march. If our body is a temple, then the heart is our sanctum sanctorum, where the chants are being read at all times. Blood carries the message known as pulse to every distant corner of the kingdom of the body, so that even the tiniest and farthest cells instantaneously know what is happening with the organism – whether it is running from a lion or lying on the couch watching a wildlife show. Pulse sets the pace for the rest of the organs, who like individual musicians must heed the conductor on how fast or slow to play their instrument in the symphony orchestra called an organism playing the musical piece called living. Lungs and limbs speed up to the tune of a frantic pulse, the stomach and guts slow down, and vice versa. At the same time, the moods and the needs of the body drive the heart. Whether we are elated and excited, or sad and depressed, the heart beats differently to show this plainly. So the body controls the heart beat and at the same time the heart beats control the body. Is this a paradox? Hardly. It is no different from a drummer, who simultaneously drums and listens to the rhythm of his or her drumming, as all musicians must.
All that is great, one might say. Are there any practical implications of the heart not being the pump, but the body’s drum? Sure! Plenty.
Every good drummer is perfectly capable of keeping a steady rhythm going, yet they tend to vary the beat ever so slightly to keep things interesting. Only drum machines and metronomes play monotonically. Not surprisingly, one sign of a healthy heart is its beat variability. A healthy heart is flexible in responding to the body’s needs, beat to beat, from inhale to exhale. It beats fast when driven to do so but slows down when not. In contrast, when faced with chronic stress, or when suffering from ill health, this drummer tenses up and loses variety in its musical repertoire. Low measures of Heart Rate Variability (HRV) are indeed associated with higher mortality. Other heart measures are more complex to interpret. A lower resting Heart Rate (HR) is touted as a good thing, but it’s complicated because an athlete may have that but then again so might an older person. Is a person with a low HR an endurance athlete or a biologically older human? In the end all that one may say is that some hearts on average beat slower than others for a variety of reasons, just as some musicians play slower music. Similarly, a plot of Maximal Heart Rate (Max HR) versus age has a lot of scatter to it. Max HR also misses the point as a measure of heart health, because it is primarily the body that drives the heart; the heart does not drive the body. The number registered on a ticker that meters flow when the system is pushing its limits in all out exercise may not say much about the ticker itself.
Knowing that heart rate variability is a good thing, one can then talk about how to get that. Aerobic exercise has become synonymous with cardiovascular exercise, but this is a mistake. It hyper-focuses on heart health as opposed to system health. Again, legs are what drive the heart, rather than the other way around. Lifting heavy weights will get the pulse going pretty quickly too, and may be a more efficient method of training the heart without breaking it from ego-driven overuse over long distance running. It is thus simplistic thinking to say that only running is cardio, and more running is always better. There seems to be a point, say 5 hours/week of running, beyond which while one still gets better at running itself, other things start to go wrong. The heart grows too big, its walls thicken with overuse, and we’re in the danger zone of hypertrophic cardiomyopathy. Steady state exercise on flat terrain over long distances, especially of a monotonous sort such as jogging and cycling, paces our heart into sinusoidal, simplistic rhythms resembling those of congestive heart failure patients. Instead, moving about at low-intensity levels over long periods, such as hiking and walking, and then mixing in short bursts of high-intensity exertion, such as lifting weights or sprinting, produces rich nerve-firing patterns with high fractal complexity. This is a rhythm unlike the dull non-music of a machine. All good drummers know to vary the beat.
Heart Rate vs Age: no real pattern; Heart Rate Variability vs Age: some signs of decline with age
There’s more to percussion music than a varied beat though. In Ayurveda, a view of the heart as a drum is elevated from mere metaphor to a sophisticated diagnostic tool for assessing the health of the individual. The pulse is studied for its variation along four parameters – rate, rhythm, intensity and volume. This allows the practitioner to characterize and distribute the patient’s body state along three significant aspects known as Vata, Pitta, and Kapha (VPK). A highly simplified description of these aspects still reveals the multi-faceted role of the heart beyond a pump. Vata governs the beating of the heart, initiates the electric spark to pulsate the heart via the sinoatrial node, and thus regulates the circulation of blood. Pitta is responsible for the purification of the blood, and is responsible for the intake and processing of emotions in the heart. Kapha is responsible for the structure of the heart and blood, and the strength of the heart. An imbalance in these three aspects typically indicates a state of ill health which can then be corrected by changes in dietary composition, exercise, and lifestyle. Recent studies have found correlations between these ancient four-parameter assessments of pulse via VPK and the modern single-parameter assessment of pulse variability via HRV in terms of predicted health. As fitness trackers grow more advanced, one may perhaps expect more subtle parallels to be unearthed along more dimensions than beat variability.
Finally, matters of the heart must take into account the topic of love. In Chinese medicine, the pericardium, which is the protective sack of cartilage in which the heart sits, is referred to as the “heart protector”. It is considered to be the first line of defense against external harm, not just of the physical sort, but also the emotional sort. It is said to play the same role as a minister in the emperor’s court. The emperor makes very important decisions, but needs space and sanity to function effectively. A wise minister controls access to the emperor and regulates incoming messages, since being flooded with too much stimulation would be overwhelming. However, an overzealous minister filters too much information. The pericardium similarly tenses up to attenuate damage to the sensitive heart from sudden unfiltered exposure to distressing events in the world outside. This is great as a temporary protective measure to dampen shock until the heart is ready to perform the critical task of processing the emotionally laden input. Yet, a perpetually tight pericardium will make the heart rigid and stiff too. Chronic guarding is the state of walking around as a tightly wound human being, as if one carries within a heart made of thin glass. To be forever in a defensive posture against a hostile world, is to be closed off to all that makes life beautiful even when it is sometimes painful. Opening the heart to receive is an act of courage. It is a risk to be open to both love – not just a narrow needy notion of romantic love, but the expansive sort – and the inevitable hurt. Yes, this makes one vulnerable, but the alternative is far worse. To muffle a drum that may have once startled us by placing a big rock over it is rather silly.
Any exquisite instrument demands to be played masterfully. The heart desires exploring its full range of rhythms, fast and slow, loud and quiet, simple and complex. At one extreme, this means occasionally exposing ourselves to bursts of high intensity, like a kid let loose with sticks to bang away on a starter set. At the other extreme, this means occasionally emulating a jazz maestro’s touch and finesse, with ghostly notes barely heard in the deepest of meditative states with the sparest of breaths. Most of the time, this means chasing the ego out of the picture and giving it gentle movement instead of round-the-clock abuse, so one does not end up beating it jarringly out of tune like a snare drum at the end of a long parade. Finally, it means keeping the instrument in proper emotional pitch, sounding neither too sharp nor too flat in response to emotional stimuli, and free of any hindrance to resonate. This then allows for the musical virtuosity that suits mother nature. It makes for the song of a happy heart.
