The Heart Matters – Part 1
By: Brad Hankins
The next few months, we will focus on the cardiovascular system (the heart and blood vessels) and the pulmonary system (the lungs). We’ll explore each system, its function, some common issues associated with it, and what we can do to keep our heart, lungs, and blood vessels healthy. Let’s start with the heart.
The ancient Greeks believed the heart was the center of intellect, emotions, and the soul. The ancient Chinese believed the heart was the seat of intelligence and the mind; to them, the heart ruled the body. In 170 CE, Galen, a curious Greek physician living in Rome, discovered that the heart is a muscle—but one unlike the rest of the body, as its fibers run in multiple directions rather than in a single direction like other muscles. Galen’s work was largely ignored until the 1700s, when it was recognized that the heart is a pump that delivers blood to every cell in the body.
In some ways, both the Greeks and the Chinese were correct. The heart does “rule” the body in that if it stops functioning for just two or three minutes, other body systems begin to die. Interestingly, the heart contains neurons—about 40,000 of them—compared to the brain’s 86 billion. These neurons are thought to have both long- and short-term memory. They allow the heart to function somewhat independently of the brain by helping regulate heart rate and how much blood is pumped. At the same time, the heart works closely with the brain through a specialized network of nerves, with about 80% of signals traveling from the heart to the brain—not the other way around. In this sense, the Greeks and Chinese may have been onto something: the heart does have a small “mind” of its own.
The heart functions as a pump (https://my.clevelandclinic.org/health/body/21704-heart) with three main systems, much like the pump that supplies water to your home. It has a mechanical system of valves and chambers that control pressure and output, an electrical system that energizes the mechanical system in sequence, and a built-in plumbing system that meets its own internal needs. All three systems work together, in a precise order, to ensure oxygenated blood reaches every cell in your body.
The cells of the heart, called cardiomyocytes, are highly specialized muscle cells. They contain more mitochondria (the cell’s “power plants”) than most other cells and consume a tremendous amount of energy. Perhaps the most fascinating aspect of these cells is that many of them are as old as you are. You were born with about 50 to 60 percent of the heart cells you have today—possibly more. While your body regenerates red blood cells every four months and liver cells every six months to a year, your heart does not fully regenerate over your lifetime.
Another way to think about this: have you ever heard of heart cancer? While primary heart cancer does exist, and metastatic cancer (which spreads from elsewhere in the body) can reach the heart, both are extremely rare. Why? Because cancer, simply put, is a disruption of cellular regeneration—and most heart cells rarely, if ever, regenerate.
Even if you are in your 70s or 80s, some of your heart cells have been beating since the day you were born. Up to half of your current heart cells have been beating 60 to 70 times per minute through kindergarten, high school PE, college exams, and decades of work.
These lifelong cells pump up to a gallon and a half of blood per minute, about 100 gallons per hour, and roughly 51 million gallons (about 1 million barrels) over the course of your life. Day and night, every day of your life, without any conscious effort, your heart is always at work.
It goes without saying: you want to do everything you can to keep your heart healthy. Since many heart cells stay with you for life and may not regenerate if damaged, it’s important to care for them and avoid injury whenever possible.
Fortunately, the heart—like all muscles—benefits from regular exercise. Physical activity, combined with a balanced diet, forms the foundation of heart health. Next month, we’ll explore cardiovascular exercise and strategies for maintaining a healthy heart throughout life.
As always I would enjoy hearing your fitness journey, please feel free to email me at hankinsb@ssymca.net
Brad Hankins RN, CPT
