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I think part of this answer can be gotten at by considering our friends in nature. As my first pathology mentor told me, one of the fascinating organisms in nature is the tardigrade (slow walker) which were named by Spallanzani (? spelling) in the 1700s. These creatures are microscopic, and often inhabit extreme environments (usually cold, I think). They are capable of "cryptobiosis" which means they can stop (or dramatically cease) their own metabolism, only to be revived later when environmental conditions improve. Since tardigrades can be recovered many many years after their entering a state of cryptobiosis, it stands to reason they do not age.
Now, if a human is frozen into virtual cryptobiosis, I don't know if they would age either. If you are frozen, would your heart stop? Blood flow cease? We are a little more complicated organisms than tardigrades.
Amazing that I remember all of this about tardigrades but all the stuff I learned yesterday about T cell lymphomas is already gone.
I took a Biology of Aging class as an undergrad (of course, that's been 7 or 8 years ago), and at that time, a lot of the aging theories were directly tied to metabolism. For example, in mammals, the size of the animal and it's metabolism are inversely correlated. Which mammals live the longest? Things like whales and elephants. Which mammals have the shortest lives? Rodents. (Even though I think the relationship breaks down within species, like with dogs).
Theoretically, higher rates of metabolism lead to higher levels of free radicals, cell membrane damage, and all that jazz. Also going along with higher metabolism is higher levels of mitotic activity, which can lead to shortening of telomeres, which leads to cell death. Theoretically, we already have a "fountain of youth" and it's telomerase. Unfortunately, cells that have telomerase activity when they aren't supposed to, usually turn into raging tumors. I think it's even been shown in study animals that increased telomerase activity reduces age-related changes, but all the animals die of multiple tumors.
As a side note, we probably already possess the technology to increase the maximum lifespan of humans. It has been shown in animals with very short lifespans (fruit flies), that if you prevent them from mating until "old age", over multiple generations, the average life span of the fruit flies increases substantially. Aging is probably the only deleterious biological function where there is no evolutionary pressure to fix the problem. The solution? No sex until you're old! Sure, it'll be several hundred years before the (theoretical )benefits show up, but you'd be doing humanity a swell favor.