Your heart will grow steadily weaker as you age, losing some of its vital pumping functions, and possibly dissolving into heart failure the number one peril after age sixty five.
But you may be able to prevent and reverse some of the disintegrating function of your heart by protecting and strengthening the workings of tiny structures (mitochondria) inside cells that produce and transport the energy that keeps the heart strong and pumping.
It’s a myth that your heart does not weaken as you get older. Several major studies suggest that heart function does not fizzle with age, that an older heart pumps just as well as a younger one. However, that may be true of a heart measured “at rest,” but it’s not true of ordinary aging hearts undergoing the normal stresses of life, according to Jeanne Y. Wei, M.D., director of the division on aging at Harvard Medical School.
Actually, the vital machinery of heart cells becomes increasingly damaged by free radical attacks as you age. Each heart cell, like other cells, has many tiny energy factories, called mitochondria, that are the “respiratory centers,” the life force of cells, that keep them alive and functioning properly.
But with age, large portions of the DNA of these mitochondria are literally chipped away. The weakened mitochondria then have to work harder, they require more oxygen. Consequently, the metabolic functioning of heart mitochondria declines by 40 percent in aged hearts, Dr. Wei says.
In aged animals, the formation of vicious super-oxide radicals in heart mitochondria surges 40 percent; mitochondria membranes become stiffened, stuffed with cholesterol and less efficient at transporting all important ionized calcium that controls heart function.
Microscopic photos of old animals’ heart mitochondria show a scarred and tangled mess compared with those of young animals. This relentless free radical damage to heart mitochondria DNA over the years can lead to enlarged hearts, diastolic dysfunction (when blood flows back into the ventricle), reduction in blood flow, and congestive heart failure, exactly the symptoms that gradually beset aging populations.
Half of all Americans have diastolic dysfunction after age eighty, and congestive heart failure is a growing epidemic, the number one cause of hospitalization for Americans over age sixty five, says Dr. Wei. Rates of congestive heart failure double every decade after age fifty.
“The old heart is simply less able to keep up. When there is something wrong with muscle function, let’s say, or you have hypertension or a touch of arrhythmia, you can’t generate enough energy to pump blood through the heart because you can’t mobilize the machinery inside each of those heart cells to keep the muscles relaxing and contracting appropriately, so the heart will go into failure,” explains Dr. Wei.
Worst of all, this cycle of damage to the heart mitochondria is self-perpetuating and accelerating. The more damaged they become over time, the less able they are to snuff out new damage, and it accumulates, picking up speed, causing more and more severe global heart dysfunction with age.