why can't we live forever?
As we grow old, our own cells begin to betray us. By unraveling the mysteries of aging, scientists may be able to make our lives longer and healthier IF YOU WERE GIVEN a free hand to plan how your life will end--your last weeks, days, hours and minutes--what would you choose? Would you, for example, want to remain in great shape right up until the last minute and then go quickly? Many people say they would choose that option, but I see an important catch. If you are feeling fine one moment, the very last thing you would want is to drop dead the next. And for your loving family and friends, who would suffer instant bereavement, your sudden death would be a cruel loss. On the other hand, coping with a long, drawn-out terminal illness is not great either, nor is the nightmare of losing a loved one into the dark wastes of dementia. We all prefer to avoid thinking about the end of life. Yet it is healthy to ask such questions, at least sometimes, for ourselves and to correctly define the goals of medical policy and research. It is also important to ask just how far science can help in efforts to cheat death. WE'RE LIVING LONGER
IT IS OFTEN SAID that our ancestors had an easier relationship with death, if only because they saw it so much more often. Just 100 years ago life expectancy was shorter by around 25 years in the West. This literal fact of life resulted because so many children and young adults perished prematurely from a whole variety of causes. A quarter of children died of infection before their fifth birthday; young women frequently succumbed to complications of childbirth; and even a young gardener, scratching his hand on a thorn, might be lost to fatal blood poisoning. Over the course of the past century sanitation and medical care so dramatically reduced death rates in the early and middle years of life that most people now pass away much later, and the population as a whole is older than ever before. Life expectancy is still increasing worldwide. In the richer countries around the world it lengthens five hours or more every day, and in many developing countries that are catching up the rate quickens still faster. Today the dominant cause of death is the aging process itself and the various diseases to which it gives rise--whether cancer, which drives cells to proliferate out of control, or Alzheimer's, at the opposite pole, which causes premature death of brain cells. Until as recently as 1990, demographers predicted confidently that the historical trend of increasing life expectancy would soon cease. Aging, many researchers believed, was fixed--a process programmed into our biology that resulted in a built-in time of death. No one foresaw the continued increase in life expectancy. It has taken our politicians and planners by surprise. Scientists are still coming to terms with the notion that aging is not fixed, that average life spans have not reached a limit. They change and continue to change, stretched for reasons that we do not fully understand. The declining death rates of the very old are now driving human life expectancy into uncharted territory. If the prevailing certainties about human aging have crumbled, what is left? What does science actually know about the aging process? Accepting new ideas is not always easy, because scientists are humans, too, and we have all grown up with fairly rigid preconceptions about how the body ages. Some years ago, while driving with my family in Africa, a goat ran under the wheels of our vehicle and was killed instantly. When I explained to my six-year-old daughter what just happened, she asked, "Was it a young goat or an old goat?" I was curious why she wanted to know. "If it was old, it's not as sad, because it wouldn't have had so long to live anyway," came her answer. I was impressed. If such sophisticated attitudes to death form this early, small wonder that modern science struggles to come to terms with the reality that most of what...
Please join StudyMode to read the full document