Ageing
Mark Sun
Immortality has become a prevalent topic among scientists and millionaires in recent years; almost everyone is trying to maintain their youth for longer. Consequently, this leaves us with a hugely important question, what are the possible causes of ageing? Many biologists have been looking into it and finding possible explanations, and many theories are being suggested. Firstly, an interesting theory called programmed senescence theory was suggested by Dr Davidovic. He proposed that ageing is an essential and innate part of human physiology, and is programmed into our bodies. Every organism is designed to have a specific life span. This is because if our body does not eventually ‘ wear out ’ , human beings will have an ever-lasting life span. Programmed ageing is the theory that senescence in humans and other organisms is caused by evolved biological mechanisms to provide an evolutionary advantage. 1 Modern programmed (adaptive) theories of biological ageing assert that, in general, organisms, including mammals, have evolved mechanisms that purposely limit their lifespans in order to acquire an evolutionary advantage. Modern non-programmed theories assert that mammalian ageing is primarily caused by natural deteriorative processes and that differences in lifespan between species are due to differences in their resistance to these processes. 2 There is evidence which supports this statement. Prinzinger found out in 1996 that the average life span of many species doesn't change too much: an elephant dies at around 70 years old, and a spider monkey dies at around 25 years old. 3 This proves that the rate of ageing of each species of organism is more likely to be programmed in their genes as there is not much variation. The neuroendocrine theory of ageing, developed by Vladimir Dilman, states: ‘ The effectiveness of the body's homeostatic adjustments decreases with age, resulting to the failure of adaptive mechanisms, ageing, and death. ’ This concept is also known as the ageing clock theory and the pacemaker theory. 4 It was discovered that as people get older, their average fasting glucose level rises from 6 to 14 milligrams per deciliter every ten years after the age of 50. Because their body cells are becoming less sensitive to insulin, which will eventually lead to diabetes; furthermore, the thyroid gland located in the neck may become lumpier after the age of 20, which leads to the metabolism slowing down over 1 Goldsmith, T. (2016) ‘Evolution of aging theories: Why modern programmed aging concepts are transforming medical research’, Biochemistry (Moscow) . 81.12:1406-1412. doi:10.1134/S0006297916120026. 2 Goldsmith, T. (2014) ‘Modern evolutionary mechanics theorie s and resolving the programmed/non- programmed aging controversy’, Biochemistry (Moscow) 79.10:1049-1055. doi:10.1134/S000629791410006X. 3 Jin K. (2010) ‘Modern Biological Theories of Aging’, Aging Dis . 1.2:72-74. 4 Diggs, J. ‘Neuroendocrine (Aging Clock) Theory of Aging’, in Encyclopaedia of Aging and Public Health . Springer US. P. 584-586. doi:10.1007/978-0-387-33754-8_313.
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