Aging is an inevitable, irreversible, predictable and universal process in all living organisms.
Senescence (growing old) is a continuum, and part of the developmental process. It begins as soon, or perhaps even before an ovum is fertilised. The rate at which aging proceeds is species specific, and humans (Homo sepiens) have the longest life-span among the mammals. It appears to be genetically programmed according to the most popular theory of aging, i.e., cellular DNA (deoxyribonucleic acid) determines the rate and pattern of senescence which is unique to every person. Normal aging is accompanied by changes in physiological parameters including heart rate, cardiac output, blood pressure, lung function, and so on. Therefore aging is both a 'normal' and a 'diseased' process.
Many theories have been elaborated to explain the process of aging: (i) Programmed theory which implies that genes are turned on and off during the whole process of development, and certain "aging genes" are the cause of senescence; (ii) Stress theory suggests that stress on the organism generates alarm, adaptation, and exhaustion. Aging is due to the ultimate "wearing down" of the organism at the cellular level. Accumulated "wear and tear" limits the capacity of the organism to repair the damage; (iii) Mutation theory correlates the aging process with irreparable mutation in the genetic material; (iv) Free radical theory propounds that "free radicals" are reactive atoms and molecules with highly excited electrons which are able to oxidatively attack certain molecules as lipids which undergo peroxidation; (vi) Slow virus infection theory states that latent viruses exist in human tissues causing slow infection and immunosuppression leading to aging; and (vi) Autoimmune theory which suggests that aging leads to production of 'autoantibodies' leading to cell damage, necrosis, and finally senescence.
Man is a lump of "desires". During childhood he desires to be 'older', and in oldage he desires to be 'younger'. Many remedies have been touted and promoted for having an anti-aging effect including:
- Hormones (Human Growth Hormone (HGH), dehydroepiandrostereone (DHEA), testosterone, oestrogens, and melatonin).
- Antioxidants (Vitamin C and E, beta-carotene, coenzyme Q10 and SOD (superoxide dismutase), and
- Other agents (magnetised waters, magnets, and light devices).
Scientific studies on this aspect of these remedies have yielded contradictory and equivocal results. In fact, the process of aging and its pathophysiology continues to be elusive. Moreover, some of the above agents on chronic use can lead to adverse reactions. Hence, a lot of further work is required. Continuing gerontologic research is likely to solve certain question about the process of aging.