The Biology of Aging
Why, after being so exquisitely assembled, do we fall apart so predictably? Why do we outlive dogs, only to be outlived by turtles? Could we catch up with them? Living to 200 is not a realistic goal for this generation, but a clearer picture of how old is already within our reach.
If only God had found a more reliable messenger. Back around the beginning of time, according to east African legend, he dispatched a scavenging bird known as halakawa to give us the instructions for endless self0renewal. The secret was simple. Whenever age or infirmity started creeping up on us, we were to shed our skins like tattered shirts. We would emerge with our youth and our health intact. Unfortunately the halakawa got hungry during his journey, and happened upon a snake who was eating a freshly killed wildebeest. In the bartering that ensued, the bird got a satisfying meal, the snake learned to molt and humankind lost its shot at immortality. People have been growing old and dying ever since.
The mystery of aging runs almost as deep as the mystery of life. During the past century, life expectancy has nearly doubled in developed countries, thanks to improvements in nutrition, sanitation and medical science. Yet the potential life span of a human being has not changed significantly since the halakawa met the snake. By age 50 every one of us, no matter how fit, will begin a slow decline in organ function and sensory acuity. And though some will enjoy another half century of robust health, our odds of living past 120 are virtually zero. Why, after being so exquisitely assembled, do we fall apart so predictably? Why do we outlive dogs, only to be outlived by turtles? And what are our prospects for catching up with them?