> I wonder to what extent it is possible to slow the damage. For instance, if you're bleeding, you may be able to slow it - but if you don't stop it completely, eventually you will bleed to death.
Yes, exactly. Well, the simplistic model is that you have a rate of damage (RD) and rate of repair/replacement (RP), and if RD > RP, the system will eventually fall apart. "Repair" consists of both your body's endogeneous repair or replacement processes and exogeneous things we might do.
Most researchers focus on RD, because it seems easier for us to do things about that. Calorie restriction probably mostly affects RD instead of RP, for example. In high theory, one could stop aging purely by lowering RD enough so that it is below the body's endogeneous RR.
But in reality, it is easier for the body to detect and repair some kinds of damage than others. It is quite hard for the body to detect DNA mutation in a cell before it starts actively causing aberrant behavior in a cell, although such mechanisms exist.
> I think it is ridiculous to believe that in a universe where galaxies die, human beings can keep going like the Duracell bunny for as long as we like
Well, at THAT timescale, we are talking about problems of physics and thermodynamics, not biology. But if you consider that in some sense life on Earth has proceeded in an unbroken chain for ~4B years, you can see that it is possible to go quite far by decreasing local entropy at the expense, of course, of global entropy. I do not see how physics prevents human lifespan of at least 10K years, but the technical problems are immense, and I do not predict major success within our lifetimes.
Yes, exactly. Well, the simplistic model is that you have a rate of damage (RD) and rate of repair/replacement (RP), and if RD > RP, the system will eventually fall apart. "Repair" consists of both your body's endogeneous repair or replacement processes and exogeneous things we might do.
Most researchers focus on RD, because it seems easier for us to do things about that. Calorie restriction probably mostly affects RD instead of RP, for example. In high theory, one could stop aging purely by lowering RD enough so that it is below the body's endogeneous RR.
But in reality, it is easier for the body to detect and repair some kinds of damage than others. It is quite hard for the body to detect DNA mutation in a cell before it starts actively causing aberrant behavior in a cell, although such mechanisms exist.
> I think it is ridiculous to believe that in a universe where galaxies die, human beings can keep going like the Duracell bunny for as long as we like
Well, at THAT timescale, we are talking about problems of physics and thermodynamics, not biology. But if you consider that in some sense life on Earth has proceeded in an unbroken chain for ~4B years, you can see that it is possible to go quite far by decreasing local entropy at the expense, of course, of global entropy. I do not see how physics prevents human lifespan of at least 10K years, but the technical problems are immense, and I do not predict major success within our lifetimes.