WHILE driving to work this morning I was contemplating writing a comment on a recent article in Nature that identified that the maximum lifespan for humans is about 115 years and not increasing.
Lo and behold, the AM current affairs program on ABC radio put up a short piece about a man who has created a start-up with the goal of enabling people to live forever. I will not cover old ground and discuss the broader consequences of us living on for even an extra 50 years. However, and leaving aside the breathless and perhaps naive enthusiasm of the budding entrepreneur (results possible in 10 to15 years?), it did remind me of some interesting questions about how we come to die from old age.
I remember being told early in my life that we grow bigger, smarter and stronger until we are about 20ish, but that it is all downhill from there. Over the course of our adult years, the communities of cells and the extracellular structures that comprise our body progressively decline as every tissue suffers insults, injuries, scarring, and wear and tear.
Whether by the misfortune of chance or the inexorable stresses of routine use, we become less fit when compared to how we were when we first reached adulthood; we accumulate damage to our DNA; our cartilage wears away, as do our teeth; our arteries and our skin lose their elasticity; the lenses in our eyes start to cloud up and our maculae degenerate. Every organ in our body slowly wears out. That is the way we are.
Most of us eventually experience the progressive failure of one or more organ systems and, after a period of medical treatment, eventually we die. Sometimes it is hard to decide what organ caused us to die. Was it the heart failure or the chronic obstructive pulmonary disease? Did the patient with cancer who decided to stop dialysis because she wanted to go home die from her tumour or renal failure?
But what happens if we don’t get any particular illness?
As a palliative care doctor, I have seen a number of people who didn’t seem to have any major organ failure, but died of what we ended up calling old age. While they had many problems, nothing seemed bad enough to be blamed for their impending death. As they declined, they just became weaker, fatigued more easily, slept more, shrank and stopped eating. Some of these people were over 100 years old, but many were younger. They were just reaching the end of their personal maximum lifespan.
While we have been very effective at treating illnesses, most medical interventions deal with one disease and part of one organ system. Modern treatments do not address the global wear and tear that affects every part of us. Ageing is not really perceived as disease, nor do we expect that it be treated as such. One day we realise that we have become old.
We vary in the rate of our decline. Some of us last for ages and can participate in seniors games into our 90s, the rest of us start to unravel earlier. While the way we live our life can influence the rate of our decline, whether at 70 or 100 years (or for the oldest of six billion, around 115 years), eventually and unless something else happens first, we all wear out and glide to a halt.
Certainly, we should strive to prolong meaningful lives of quality by whatever technology we can afford. At the same time, life is much easier to live when we accept that dying is the normal culmination to what has hopefully been a long, productive and fulfilling life, particularly if we know we will be cared for to the very end of our lives, however long they may be.
We have evolved living our lives with the goal of being replaced by our children, and they in turn by theirs. Dreams of immortality simply serve to distract from the complexity of living in the present and dealing with death. If we lived forever there would be no reason to have children – now, that would be sad.
Associate Professor Will Cairns is Queensland’s Clinical Lead for Care at the End of Life and author of the eBook Death Rules – how death shapes life on earth, and what it means for us.
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