Live long and prosper: why we dieMen in white lab coats have been pondering the reasons behind our imminent mortality as long as there have been men to wear white coats. And, anticlimactic though it may seem, they say that sex is the answer. We reproduce. We age. And we die. "The price we pay for sex is death," explains S. Jay Olshansky, Ph.D., associate professor, biodemographer, and scientist in the department of medicine at the University of Chicago, Division of Biological Sciences, Pritzker School of Medicine. Once we have reproduced and passed on our genes, we as individuals are disposable. But, says Dr. Olshansky, we have already attained a true measure of immortality because our genetic material is passed on through sex from generation to generation. "Our immortality lies in our genes," he says. All of this happens at a species level. Because humans are a sexually reproducing species, all humans, regardless of whether they reproduce, will die. A life of abstinence won't make you live longer. As the old joke goes, it will just feel like it. This system benefits humankind in the long haul, albeit not necessarily you. Your one consolation is that the process of passing on your genes (that is, sex) is a whole lot of fun. Talking about Evolution The current life-death cycle leaves room for variety in the species, giving our genes the chance to adapt to an ever-changing environment, explains Dr. Olshansky. Each generation can adapt as the world changes and then can pass those adapted genes on to the next generation, he says. There is a careful orchestration of all our living and dying. "The life spans of most species are linked to their reproductive periods," Dr. Olshansky says. "Mice and insects have short reproductive periods and very short lives. Humans, elephants, and turtles have long reproductive periods and, consequently, long life spans." The connection is so strong that some researchers are even investigating how pushing back the reproductive period can extend life. "We've already done it with fruit flies," says Leonard Guarente, Ph.D., professor of biology at the Massachusetts Institute of Technology in Cambridge. "If you force them to mate late, over a few generations, you end up with flies that like mating late and that live longer." But alas, they still age and die-and so do we-despite our best attempts to foil Mother Nature, says George Webster, Ph.D., researcher in molecular biology and aging in Satellite Beach, Florida, and author of Hello, Methuselah/: Living to 100 and Beyond. Biologists have determined that each cell in an organism will divide only so many times before it shuts down and becomes inactive, Dr. Webster says. What they haven't figured out yet is how cells decide when they're going to shut down. The wear and tear of living also pushes this process along, says Siegfried Hekimi, Ph.D., professor of biology at McGill University in Montreal. "You accumulate defects from being alive," he says. "Cells get damaged. Cells wear out. You can slow this down, but there's no way to completely avoid it." Beating the clock Okay, so death is inevitable. But dying before our time is not. Granted, millions of men do make a hasty exit from the human race long before they're ready to pass the baton, but that's not because they're built that way. Often, they simply do things to accelerate the process. The saying "live fast, die young" applies here, says Dr. Webster. "Men smoke. They eat fatty foods. They watch television. They sit around and don't exercise. They do all these wrong things. Then they end up with real trouble like heart disease or cancer and act like it's a sudden occurrence," he says. "Those diseases aren't a consequence of aging; they're a consequence of living poorly. Start laying plaque in your arteries, and you'll end up with heart disease. Injure your cells with toxins from cigarette smoke, and you'll get cancer." And even if you somehow escape disease from the damage you've done, you may still accelerate the aging process, so you won't live as well or as long as you should have, adds Dr. Hekimi. You can affect how long your cells continue to reproduce healthily by taking care of yourself, Dr. Hekimi says. "It's not like your clock is going tick, tock, tick, tock-bang!-you're dead." Your environment, especially your lifestyle, influences the ticking of that clock, he says. "You know what to do to live as long as you're supposed to," Dr. Hekimi says. "Don't smoke. Drink in moderation. Be active, but don't overdo it. Don't work too hard. Don't eat garbage." Living to your maximum life span is mostly in your own hands. Experts can tell you what to do. But then you have to do the rest. *1/36/5* GENERAL HEALTH «Buy Generic Cialis» |