Appliance of Science: Why do we age?
It is one thing we all have in common but why do we age and what happens to our bodies as we do?
What is aging?
Aging may be defined as the process of becoming older, a process that is genetically determined and environmentally modulated.
The definition of aging varies depending on who you ask and what age they are. Some people find a new sense of self and purpose as they age, leading to the new term gerontolesence, referring to a type of second adolescence in 50 to 75 year olds. However young we feel, our bodies are still changing as we age.
What happens as we age?
Our bodies are constantly correcting for errors in our everyday biological processes as well as dealing with attacks from within our environment. The more issues the body deals with, the more errors can arise. Couple this with the fact that most of the cells in our bodies are programmed to die after a certain number of replications and we begin to understand the aging process.
There are many aspects to the process of aging, here are just a few:
Telomeres are repetitive pieces of DNA (junk DNA) found at the end of our chromosomes (our coiled up strands of DNA). When our DNA is replicating our telomeres get shortened in the process. With each replication we lose more of the protective cap until eventually the telomeres are gone, exposing functional DNA to the same trimming error.
as we age, the energy producing mechanisms or our bodies start to malfunction, causing a build-up of toxic products (free radicals) that can damage or kill our healthy cells.
it is not just a deterioration in our sight and hearing that interfere with our communication as we age, there are problems within our bodies too. The signalling pathways between cells, our immune system, our hormonal control system and our nervous systems all tend to disimprove over time.
What can we learn from other animals?
When we look at the aging processes of other mammals we see that, in general, animals that are under the greatest threat will reproduce earlier and die younger. While those that have fewer predators tend to live longer lives. Think mouse versus elephant.
When we think of longevity the naked mole rat probably doesn’t spring to mind. However this bald, blind and very wrinkled rodent can outlive its cousins by decades. What is its secret? It appears that their cells regenerate the degrading telomeres. If we were to introduce the same practice into all of our cells we run into major cancer risks.
Then there is the hydra that seems to have discovered the secret to immortality. When under severe environmental threat they regress through the stages of their life cycles until conditions become more favourable. This approach may have worked for Benjamin Button but is not a realistic anti-aging plan for us.
So, why do we age?
Perhaps our primary task is to pass on the genetic code to the next generation or maybe aging is part of the process of adapting and evolving as a species. After all, even the hydra’s immortal tactics cannot stop it being eaten by a predator.
