It is not very large—in fact, it is only a little larger than your closed fist. Yet its small size belies the unique and vital role it plays in your life. Indeed, without it you would have no life at all! Hour by hour, minute by minute and even second by second, you depend on it utterly, yet unless there is something wrong with it we often fail to give it a second thought.
What is it? It is the human heart—a biological marvel of God's creation that would be the pride of any engineer on the planet. Consider just a few of the reasons we should appreciate this masterwork of our Creator, this miracle that stays quietly and constantly beating within our chests.
One of the heart's main purposes is to keep blood coursing through our bodies, collecting from our lungs the much-needed oxygen it distributes throughout the body. To do this, the one heart has to receive blood simultaneously from two different sources—the lungs and the body—and send it back out in two different directions. The ingeniously designed and deceptively simple structure of the heart makes this feat possible.
In the first step, the heart receives blood in its top two chambers: the atria. The right atrium fills with "used" oxygen-depleted blood from the body, while the left atrium fills with "fresh" oxygen-rich blood from the lungs. With a squeeze, the atria send their individual contents to two larger, muscular ventricles below them. Then, with a second squeeze, the right ventricle sends the "used" blood to the lungs for a fresh load of oxygen, while the left ventricle simultaneously sends its "fresh" blood to the rest of the hungry body.
As marvelous as these muscular chambers may be, they could not do their job without the four one-way valves that open and close at just the right times to keep blood flowing in the right direction. In fact, it is the perfectly timed closing of these valves—in synchronized pairs—that creates the familiar "lub-dub" sound of your heartbeat. "Lub"—two valves below the atria slam shut as the ventricles send blood into the body. "Dub"—those atrial valves reopen while the other pair slam shut so the ventricles can be filled again.
"Lub-dub… lub-dub… lub-dub…" That simple sound emanating from your chest represents an intricately designed dance of muscle, nerve and valve that keeps you alive, every second of every day!
And when did this dance begin? Your heart began to beat only three weeks after your conception, when you were the size of a mere poppy seed! Even before you had a brain, your heart was already working hard at the job it will perform for the rest of your life.
With that in mind, try this: quickly squeeze your hand into a tight fist and then open it back again, over and over, at a rate of 70 times per minute. How long does it take before your hand and arm muscles are tired and weary?
Consider, by comparison, that the heart works continuously, resting only during the tiny fraction of a second between each heartbeat. In order to accomplish this (literally) tireless task, God equips the heart with specialized cardiac muscles that contain 15 to 30 times more "energy generators" (mitochondria) by volume than your other muscles.
As a result of all this work, the heart racks up some impressive statistics! For someone who lives to be 75 years old, the average heart's work will comprise more than 2.7 billion heartbeats! Even in a single day, most hearts will beat around 100,000 times. Over those 75 years, a heart will pump more than a million barrels of blood—enough to fill two to four long-range oil tankers!
And yet, as impressive as all this is, the heart must be more than a mere "pump" to keep us alive. It must "know" the needs of our body at any given moment and be able to instantly respond with a change in pace—with extreme precision and accuracy—to meet those needs. If it did not, even the simple act of standing up would cause disorientation and even fainting!
So, how does the heart "know" what you are doing? To "decide" what our heart rate should be at any given moment, it must intelligently process information simultaneously from three sources: the brain, the hormone levels in our blood and the heart's very own internal nervous system—with its own collection of around 40,000 neurons, much like the brain's own neurons!
Along with its own unique nervous system, the heart has its own internal power source! Specialized bundles of neurons in the heart both generate each electrical impulse that makes the muscles contract and also regulate that impulse, ensuring that its trip through the muscles is delayed halfway through for a precise fraction of a second that keep the atria and ventricles in sync, one beating after the other.
While all of this may sound like we fully understand the human heart—and it is one of the most intensely studied organs in the entire body—this marvel of God's creation still holds so many mysteries.
For example, in April 2016 scientists from the University of Waterloo announced that there seems to be some sort of correlation between individuals' heart rates and their wisdom. They found that individuals whose heart rates experienced wider variation were also more likely to display less-biased judgments from a third-person point of view.
Why would one's heart rate be related in any way to wisdom in perception and judgment?
One is tempted to consider Bible verses such as Proverbs 2:10–11: "When wisdom enters your heart and knowledge is pleasant to your soul, discretion will preserve you; understanding will keep you…."
The more we reflect on this wonderful marvel beating in our chests, the more it might make sense that God would use it to symbolize the very center of our emotion, sentiment and care—the center of our life. Furthermore, just as it is so vital to maintain a healthy physical heart for good health and a long and vibrant life, so too does God tell us: "Guard your heart above all else, for it determines the course of your life" (Proverbs 4:23, NLT).
A biomechanical pump of ingenious design and an information-processing machine of virtually instant response and astonishing precision—our lives depend on this marvelously coordinated, highly "intelligent" system doing its job without fail, every day of our lives.
When you need a reminder of the greatness of God and how His love for us is displayed through His design, consider placing your fingers on your wrist or neck and feeling your pulse for a few moments—listening to the rhythmic hymn our heart continually sings to its remarkable Designer. And let every beat you feel remind you that you truly are "fearfully and wonderfully made" (Psalm 139:14)!