It is cruel that the longer we live on this earth, the less we can enjoy it. The mythical prince Tithonus of Troy was made immortal, a gift to his lover Eos, Goddess of the Dawn, from Zeus himself. Unfortunately, she had forgotten to ask for eternal youth, and the body of the unlucky Trojan degraded until he became a cicada for the rest of time. Ageing is not a disease- not only does it cross all species barriers, but it also occurs in pretty much every multicellular animal that reaches a fixed size at reproductive maturity. Effectively it refers to the weakening and damaging of the body’s ability to perform its functions in both an aggregate and specific manner.

Ultimately the problem of ageing is tied to the ‘longevity’ of an organism, that is to say, the period it can largely be expected to ‘last’ after reproductive maturity has been passed assuming there are normal material conditions until death. A large number of factors are relevant to this, with many directly determined by genetics, such as an individual’s resistance to age-related diseases such as Alzheimer’s. Others are more complicated, decided by a range of genetic and situational factors, such as the rate of repair and maintenance of various components of the body itself. The structural integrity of the body as a whole, as well as its organs, is massively affected not only by genetics but outside influences such as nutrition, with certain self-destructive actions such as smoking resulting in life expectancy falling by up to 10 years. Research done in 2006 suggests that 25-32% of the variation in the life span of a human adult is the result of genetic variations.

We have tried to explain the omnipresent process of ageing using several theories. Strehler determined that any approach to answering this question must be able to explain its universal, intrinsic, progressive and deleterious nature. One potential explanation is the concept that random errors made overtime at the point when biomolecules are copied eventually accumulate to the point that the ability of the body to carry out a certain function which depends on those molecules is drastically reduced. An example of this would involve the lock and key model for enzymes – if there were structural changes in a certain enzyme, it would no longer be able to work as efficiently. Given the very high concentrations of energy in these molecules, decay is very common due to thermodynamic principles and entropy. Usually, up until the point of reproductive maturity, internal maintenance is sufficient to prevent errors from resulting in serious damage. However, the processes of maintenance are themselves weakened by this exact loss of molecular of fidelity, meaning that over longer periods such repair becomes less effective.

Interestingly, some posit that the human body is designed to age as it exists over time. Once an individual is no longer able to reproduce, there is a possibility that it is ‘intended’ to slowly break down over time because there ultimately is no evolutionary advantage to living for long periods after the window in which one can reproduce has passed. Indeed, ageing allows for the mitigation of potential overpopulation within a community of organisms, allowing them greater access to sparse resources. It has been suggested that the continual replacement of past generations (which are guaranteed to die due to ageing) with new sets of organisms allows for a species that can better adapt to its environment.

Furthermore, the life of most multi-cellular organisms is maintained by the constant replacement of cells. This is largely done using DNA as a means of conveying information about the structure of a cell. When the enzyme polymerase transcribes DNA, there is always a tiny shortening due to the inevitable fact that the entire sequence cannot always be copied. Telomeres exist to act as a buffer to prevent damage from happening. Eventually, this buffer is exhausted after a fixed number of replications, resulting in damage to crucial pieces of DNA. American anatomist Leonard Hayflick in 1961 studied this phenomenon, estimating as a result that the upper limit of the human lifespan is around 115 years. Only 47 humans so far have been recorded to have reached an age older than this. The damage that is likely to occur includes cell loss, tissue atrophy, and greater occurrences of diseases such as cancer, as a direct result of uncontrolled mutations.

Last year I had the privilege of listening to a talk at Eton about ageing by the scientist Aubrey de Grey (who fittingly comes with a large grey beard), who is at the forefront of the effort to find a means of preventing or mitigating ageing as Chief Science Officer of the SENS Research Foundation. He has stated that he believes that the first person to live to 1,000 has already been born, given the likely development of technological interventions that will vastly increase our ability to combat ageing. He told me afterwards in an email that it was probable that the first processes to extend lifespans by several decades would be ‘rejuvenation therapies’, helping those who are already nearing their natural life expectancy, therefore buying them time for further developments to occur. Once such a ‘longevity escape velocity’ has been reached, he claims that the sky is the limit due to the exponential nature of scientific progress in an age that is vastly increasing humanity’s capabilities in data analysis. Whilst his theory has yet to be verified, we will probably be the very lucky beneficiaries of research that will provide that which was confined to myth. The economic, social, political consequences of such progress would hugely shape the society in which we live.

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