Saturday, May 31, 2008

Some Life Extension Implications

My post on the medical advances associated with Cloning naturally leads to thoughts on the ultimate medical advances: life extension and ultimately the potential for immortality. The latter is too big a topic for one post; I'll deal with that later. But we may be on the verge of being able to replace or repair nearly any of our broken parts, and consequently live for a very long time. If you eliminate disease, leaving only accidents, suicide, and homicide as causes of death, we might reasonably achieve a life expectancy of around a thousand years. What can we reasonably expect?

I'd like to ignore magical treatments that let us each pick our preferred biological age and stay there (or return there). I'd hate to have to pick an age to stabilize at--I'd only realize it was the right age after it had passed. And there are good reasons to think that medical advances could repair or replace damaged organs, but can we move backwards? Is there any possibility of a medical technology that can reverse our built-in physical changes?

Let's assume for the minute that we can (someday) stop those portions of the aging or maturation processes that lead to death.

Now consider the physiological changes that humans undergo from early physical maturity to (for example) late middle-age. (A side track: I can distinguish the average 20-year-old female body from a 25-year-old female body at a distance with only a glance. The 25-year-old looks much more female and desirable, to me.)

Back to physiological changes. We grow more slouched. Some parts sag. We grow wider and less slender. (A side track: In my mid-twenties, I had a 30 inch hip measurement and broad shoulders, a classic male V shape. Even without excessive weight gain, my hips have significantly broadened over time--the structure and shape of the bones of my pelvic girdle are no longer as narrow as they once were. I have less and less of that classic V. At the same time, my chest has deepened. Damn.)

Our bones are constantly being rebuilt. This process keeps us strong, repairs damage, responds to stresses. Likewise with our muscle structures. Older healthy men and women tend to be stronger yet with slower speed, slower reflexes, and less flexibility than younger ones. And also likewise with cartilage (ears, noses, joints). We do tend to change shape as we age, and not simply because of gravity. Rebuilding of body parts is a necessary aspect of having an endoskeleton. I would expect that changes like these will continue as we pass current limits on mortality.

What is the result? A healthy 200-year-old is likely to be noticeably wider, likely shorter, and certainly deeper than a youngster. Barring cosmetic surgery, the matured person may display larger joints, flatter feet, larger hands. Please, someone find a way to rebuild my aching back. And why has my butt gotten flatter as I age? Sitting? I believe that, with only a distant glance, we'll be able to tell a 200-year-old from a 50-year-old.

I do hope that we can repair our aging skin, eliminating wrinkles, age spots, and the myriad flaws of moles and freckles that we seem to accumulate over the years. Young skin is so much prettier. And please, doctors, find a way to do it without removing all of the old so we can grow nice fresh skin. I'd hate to have patchwork skin for a year or two as sections are removed for regeneration.

What will the average normal, healthy, 500-hundred-year-old man or woman look like?

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