Friday, May 11, 2007

The Current Reality of Aging

This New Yorker article describes the current state of the aging process in North America. The reality is particularly stark for those without close family and friends, and with few assets.
By the age of sixty, Americans have lost, on average, a third of their teeth. After eighty-five, almost forty per cent have no teeth at all.

Even as our bones and teeth soften, the rest of our body hardens. Blood vessels, joints, the muscle and valves of the heart, and even the lungs pick up substantial deposits of calcium and turn stiff. Under a microscope, the vessels and soft tissues display the same form of calcium that you find in bone. When you reach inside an elderly patient during surgery, the aorta and other major vessels often feel crunchy under your fingers. A recent study has found that loss of bone density may be an even better predictor of death from atherosclerotic disease than cholesterol levels. As we age, it’s as if the calcium flows out of our skeletons and into our tissues.

To maintain the same volume of blood flow through narrowed and stiffened blood vessels, the heart has to generate increased pressure. As a result, more than half of us develop hypertension by the age of sixty-five. The heart becomes thicker-walled from having to pump against the pressure, and less able to respond to the demands of exertion. The peak output of the heart decreases steadily from the age of thirty. People become gradually less able to run as far or as fast as they used to, or to climb a flight of stairs without becoming short of breath.

Why we age is the subject of vigorous debate. The classical view is that aging happens because of random wear and tear. A newer view holds that aging is more orderly and genetically driven. Proponents of this view point out that animals of similar species and exposure to wear and tear have markedly different life spans. The Canada goose has a longevity of 23.5 years; the emperor goose only 6.3 years. Perhaps animals are like plants, with lives that are, to a large extent, internally governed. Certain species of bamboo, for instance, form a dense stand that grows and flourishes for a hundred years, flowers all at once, and then dies.

The idea that living things shut down and not just wear down has received substantial support in the past decade. Researchers working with the now famous worm C. elegans (two of the last five Nobel Prizes in medicine went to scientists doing work on the little nematode) were able to produce worms that live more than twice as long and age more slowly by altering a single gene. Scientists have since come up with single-gene alterations that increase the life spans of Drosophila fruit flies, mice, and yeast.

The full article is well worth reading, if for no other reason, to understand what gerontologists are trying to fight, and to motivate you to support anti-aging research.

Everyone wants to live forever, but no one wants to grow old. It is a conundrum which only very clear and creative thinking can solve.


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