Working Hard for Life!
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.