If in the past, life expectancy was 50ish, and is now expected to rise to 100, would this mean that signs of aging (grey hair, wrinkles, bones and muscles becoming weaker) would happen later in life at around 70-80?
In: Biology
There are theories that there is an upper limit to natural human aging, that ~125 is just about as old as you can go, no matter how ideal your health and environment get. As it is, signs of aging aren’t delaying – we’re still all starting to gray in our 30s, etc.
That said, of course we are trying to extend life well beyond natural boundaries, and there’s nothing known that is inherently preventing us from artificially extending life. I think it’s a bit optimistic, but some like Aubrey de Grey say the first person to live 1,000 years has already been borne. Listening to him talk about it, he says all the big problems with essentially indefinite aging have been solved, there’s now just a lot of little problems.
If we’re going to live this long, we’re going to want to deal with all the degradations of our various tissues. No one wants to be a brittle old man for a thousand years. And in such a long lifetime, you’ll lose your teeth, you’ll probably lose eyes, or fingers, and so we’ll want to be able to repair damage that is statistically unavoidable and otherwise permanent. What would you do for a thousand years missing your arms?
Aging to death isn’t inherent to life, it’s actually an evolutionary strategy. It’s both offensive and defensive. Offensive, in that future generations can adapt to take advantage of their environment and be more competitive. Defensive, in that by dying, you make space for those future generations, and the population isn’t essentially static and vulnerable to mutating and evolving competitors – viruses and bacteria, principally. One good pandemic could wipe out the whole species if it wasn’t in a state of constant, fast paced evolution. And indeed, there are species that are effectively immortal – some jellyfish are very famous for this property. We speculate many species of sharks can be immortal, as well. Yes, they breed and reproduce as well, but their populations don’t see endless growth like ours do, and they have different selection pressures on them that long life is an effective strategy for them, and has been for millions of years.
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