Fix

STRONGER SPHINCTER MUSCLES IN BLADDER AND MORE DURABLE LIGAMENTS Would increase control over bladder function

Larger ligament

STRONGER SPHINCTER MUSCLES IN BLADDER AND MORE DURABLE LIGAMENTS Would increase control over bladder function

Larger ligament

Stronger wall muscle

Larger sphincter

Stronger wall muscle

Larger sphincter

www.sciam.com SCIENTIFIC AMERICAN 99

COPYRIGHT 2003 SCIENTIFIC AMERICAN, INC.

We need to EXPLOIT OUR KNOWLEDGE of evolution to enhance our quality of life as we grow older.

not designed by evolution for extended survival, so it is not their fault that they ultimately suffer age-related ailments. Most of what goes wrong with us as we grow older is a product of operating our living machines beyond their biological warranty period. Although we have considerable control over the quality of our lives at any age, there is little we can do about the length of our lives other than shorten them.

Even the term "flaw" requires clarification. Living things, and everything they make, eventually fail. The cause of failure is a flaw only when the failure is premature. A race car that fails beyond the end of the race has no engineering flaws. In the same way, bodies that fail in the postreproductive span of life may contain numerous design oddities, but they have no design flaws as far as evolution goes. Aging, disease and death are natural by-products of bodies that were optimized for reproduction.

There are countless other aspects of human biology that would merit modification if health and longevity were nature's primary objective. For example, gerontologists theorize that aging is caused, in part, by a combination of the molecular damage that inevitably arises from operating the machinery of life within cells and the imperfect mechanisms for molecular surveillance, maintenance and repair that permit damage to accumulate over time. If this view of the aging process is correct, then modifying these molecular processes to lessen the severity or accumulation of damage, or to enhance the maintenance and repair processes, should have a beneficial impact on health and longevity. These wondrous modifications, however, would have little effect unless the common sense that is needed to avoid destructive lifestyles becomes more widespread among people.

Living things are exceedingly complex, and experience teaches us that undesirable consequences invariably arise whenever humans have taken over the reins of evolution in order to

S. JAY OLSHANSKY, BRUCE A. CARNES and ROBERT N. BUTLER all have an enduring interest in the processes that underlie human aging. Olshansky is professor in the School of Public Health at the University of Illinois at Chicago. He and Carnes, both senior research scientists at the National Opinion Research Center/Center on Aging at the University of Chicago, collaborate on studies— funded by the National Institute on Aging (NIA) and NASA—of the biodemography of aging (examining the biological reasons for age-related patterns of disease and death in populations). They are co-authors of The Quest for Immortality: Science at the Frontiers of Aging (W. W. Norton, 2001). Butler is president of the International Longevity Center in New York City and was founding director of the NIA.

modify organisms (microbes, plants and animals) to suit their purposes. The most worrisome trade-off for genetic manipulation directed toward living longer would be an extension of frailty and disability rather than an extension of youthful health and vitality.

Though cobbled together by the blind eye of evolution, humans have proved to be a remarkably successful species. We have outcompeted almost every organism that we have encountered, with the notable exception of microbes. We have blanketed the earth and even walked on the moon. We are also one of the only species that has figured out how to escape premature death and survive to old age.

At this point in history, we need to exploit our expanding knowledge of evolution to enhance the quality of our lives as we grow older, because the single-minded pursuit of life extension without considering health extension could be disastrous.

Our fanciful designs of anatomically "fixed" humans are not intended as a realistic exercise in biomechanical engineering. Given what is known today about human aging, if the task of designing a healthy long-lived human from scratch were given to a team comprising the father of evolution, Charles Darwin, the great painter Michelangelo, and the master engineer and scientist Leonardo da Vinci, they most certainly would have fashioned a living machine that differs from the one we now occupy. Indeed, anyone who tries his hand at redesign would probably construct a human body that would look unlike the ones we've created on these pages. Yet we invoke this approach as an instructive way of communicating the important message from evolutionary theory that, to a significant degree, the potential length of our lives and, to a lesser degree, the duration of health and vitality are genetic legacies from our ancient ancestors, who needed to mature quickly to produce children before they were killed by the hostile forces of nature. 05

How To Add Ten Years To Your Life

How To Add Ten Years To Your Life

When over eighty years of age, the poet Bryant said that he had added more than ten years to his life by taking a simple exercise while dressing in the morning. Those who knew Bryant and the facts of his life never doubted the truth of this statement.

Get My Free Ebook


Post a comment