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This week, we start a multi-part series on aging.
Topics of discussion will center on golden year club members, time-testers, pensioners, seasoned survivors, snow birds, and retirees. I have had many opportunities to address audiences drawn from this ever-increasing demographic and still find myself lost at how best to address this group. How do you know whom to include in this bunch? In general, they have been around the block and learned a thing or two on the way. Youth and vigor are always on their mind. The only thing worse than a four-letter word is a three-letter word spelt O-L-D as Fred Hilditch's gang was quick to point out. Things once clear are now blurry, open things become blocked, and some things remain firm but in the wrong places. Dryness replaces wetness and funerals begin to outnumber weddings.
As we desiccate, shrink and shrivel, it is worthwhile to attempt to understand how this process functions. It is your best chance to stay ahead of it. The process of growing old is probably better referred to as senescence. Some people now believe that "aging" is solely due to an accumulation of damage to your DNA resulting in loss of the ability for your cells to divide. They feel that free radicals are the main culprits. These are molecules such as super oxide and nitric oxide with unpaired electrons in their outer orbits. They are highly reactive and can damage proteins, lipids and especially DNA. They often result from our poor food choices.
If it were as simple as accumulated DNA damage, then we would expect to see a wide range of older people. Currently, there is an upper limit to human chronological age. Our maximum life span seems to be between 115-120 years. Human cells lose the ability to duplicate themselves after about fifty repetitions. Interestingly, this magic number of 50 seems to hold steady across the animal kingdom. The cells in birds with a two-year lifespan or those in a 150 year old giant tortoise lose abilities after fifty multiplications. As we slowly lose that ability, things start to look it. Another widely accepted theory of aging suggests that certain cells are preprogrammed to only last a certain amount of time. The programming can vary within your body. For example, the female reproductive organs seem to age the fastest and lose their function by age fifty. Menopause is a relatively new concept in human history. For most of the last millennium, women rarely made it to that age so that cellular preprogramming may not have mattered. But even today, women tend to outlive men. So, the loss of sex hormones may be linked to aging. Historically, eunuchs, who are males without testes, tended to live longer as do sterilized cats and dogs. The commonest cause of death of the elderly in our culture is cardiovascular disease. Estrogen is a sex hormone that until recently has been naturally augmented when ovarian supplies fail. In addition to the numerous beneficial actions, recent data has noted a slight increase in cardiovascular problems with its use.
The advent of better sanitation and medical care has increased our life expectancy significantly. Curing disease will get more people closer to the 120 maximum, but not beyond. Living a perfect life punctuated with the perfect diet can only get us so far. With a lot more older folks around, someone had to study and look after them, so a whole new field of medicine called Geriatrics came to be. Interestingly, it is accepted that more and more people are not dying of any particular disease, but simply "old age". Cellular repair mechanisms in essential organs such as heart and lung cease to function. This lends support to the genetic program theory of cell death. It also provides hope. By unlocking the code for the cascade of proteins or enzymes that terminate cell propagation we might be able to block it. This might result in an unlimited ability to repair and multiply and raise life expectancy into the hundreds of years.
