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The March issue of Scientific American discusses longevity genes, and what might be done with a greater understanding of how some people resist aging so much better than others:
You can assume quite a bit about the state of a used car just from its mileage and model year. The wear and tear of heavy driving and the passage of time will have taken an inevitable toll. The same appears to be true of aging in people, but the analogy is flawed because of a crucial difference between inanimate machines and living creatures: deterioration is not inexorable in biological systems, which can respond to their environments and use their own energy to defend and repair themselves.
At one time, scientists believed aging to be not just deterioration but an active continuation of an organism's genetically programmed development. Once an individual achieved maturity, "aging genes" began to direct its progress toward the grave. This idea has been discredited, and conventional wisdom now holds that aging really is just wearing out over time because the body's normal maintenance and repair mechanisms simply wane. Evolutionary natural selection, the logic goes, has no reason to keep them working once an organism has passed its reproductive age.
While programmed aging has given way to the wear and tear viewpoint - best expressed in the reliability theory of aging - it is certainly the case that our genes determine much of the response to that wear and tear (in the form of accumulated biochemical and genetic damage in and around your cells). The reductionist view of aging clearly points to a narrow taxonomy of options for living a longer, healthier life:
- Reduce your exposure to events and processes that cause damage
- Be more resistant to the modes of damage - suffer less damage for the same level of exposure
- Be more resistant to developing disease and medical conditions as a result of accumulated damage - have a higher damage tolerance
- Repair the damage before it reaches problem levels
Your genes determine (b) and (c), and there is always the possibility that greater understanding of how and why this is the case - going all the way down to the level of biochemical processes - will lead to medical technologies that can provide the similar or greater benefits.
Sadly, anything other than (d) - in essence, the development of working anti-aging medical technology within your lifetime - will still see you suffering some form of age-related degeneration. In the grand scheme of things, doing just as well as a centenarian would be a large gain in life span for many, but it's simply nowhere near the outer limits of what is possible.
Technorati tags: aging, longevity, life extension
Posted by Reason at February 14, 2006 9:41 PM
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