Monday, 14 September 2009

Why people die and how we can live longer and better (Part 1 of 2)

If human beings were happy all the time, there would be little need for philosophy. If transactions never went wrong, there would be no market for lawyers and arbitration services. If individuals never became sick and died, few persons would choose to become medical doctors. In this light, death is not only the ultimate justification for medicine, but also its most crucial subject of study.

Statistics tell us why people die, but we have to realize that there is much more to death than what the eye can perceive. Road accidents, heart failure, stroke, and cancer occupy prominent positions in every country's causes of decease. Contemporary data point out as well the growing death toll taken by age-related sicknesses such as Parkinson and Alzheimer.

Those statistics show the immediate causes of decease, but do not address the fundamental question of why people have to die in the first place. This issue should not to be dismissed as trivial. On the contrary, unless we get a clear idea of why we must die, statistical data become irrelevant. After all, one could argue, if we are doomed to pass away at 80, who cares if you die of cancer or diabetes?

All animals expire at a certain point and we take for granted that Nature has foreseen a particular lifespan for each species, but is this really true? Could science extend man's life and push death away, decade after decade, allowing individuals to become hundreds of years old before their final demise?

The world shows many examples of men and women who have lived longer than a century. What prevents us from transforming their exceptional longevity into a general rule that would be applicable to all citizens? Nowadays, even if we could eliminate accidents as a cause of death, we would still be left with epidemics such as cancer and cardiovascular disease. Will they ever be eradicated?

Scientists have put forward many different theories to explain why animals die but, during the last sixty years, most of those hypotheses have been abandoned due to insufficient evidence. The two theories that have remained are considered, in the present stage of knowledge, as work in progress which, so far, seems to be pointing in the right direction.
  • The waste theory considers death as the final consequence of biochemical decay. From the first moment that an animal begins to breath, its cells act as miniature biological converters that turn oxygen and other substances into chemical products that are consumed to keep the organism alive. That conversion process generates a certain amount of biological waste which slowly accumulates in the body. When the amount of chemical waste surpasses the body's ability to deal with it, the animal dies.
  • The exhaustion hypothesis regards death as the natural depletion of the body's capacity to replace its own cells. While an animal is alive, its cells are continuously dying and being replaced by new cells, which are almost identical to the ones that have died. According to this theory, cells can only reproduce themselves a limited number of times without losing important genetic information. This limitation is what determines the maximum lifespan of each species, which in the case of human beings is estimated to be around 120 years.
When you hear about these two theories, you realize how little sense death statistics make. Indeed, if these hypotheses prove to be true, there might be a common reason for the most widespread causes of death such as cancer, Alzheimer, and cardiovascular disease. Would it be possible that those individual sicknesses are nothing but symptoms of a general process of biochemical waste-accumulation and cellular exhaustion? If that is the case, the practical consequences are earth-shattering.

To be continued in Part 2.


[Image by cliff1066 under Creative Commons Attribution License. See the license terms under]