While aging processes can be divided into three general categories -- genetic, biochemical, and physiological, theories of aging fall into two categories.

The "programmed" theories hold that aging follows a biological timetable, perhaps a continuation of the one that regulates childhood growth and development. The damage or error theories emphasize environmental assaults to our systems that gradually cause things to go wrong. It's important to note, many of the theories of aging are not mutually exclusive.

Here is a brief and very simplified rundown of the major theories.

Programmed Theories

• Programmed Senescence. Aging is the result of the sequential switching on and off of certain genes, with senescence being defined as the time when age-associated deficits are manifested.
• Endocrine Theory. Biological clocks act through hormones to control the pace of aging.
• Immunological Theory. A programmed decline in immune system functions leads to an increased vulnerability to infectious disease and thus aging and death.
  

Error Theories

• Wear and Tear. Cells and tissues have vital parts that wear out.
• Rate of Living. The greater an organism's rate of oxygen basal metabolism, the shorter its life span.
• Crosslinking. An accumulation of crosslinked proteins damages cells and tissues, slowing down bodily processes.
• Free Radicals. Accumulated damage caused by oxygen radicals causes cells and eventually organs to stop functioning.
• Error Catastrophe. Damage to mechanisms that synthesize proteins results in faulty proteins which accumulate to a level that causes catastrophic damage to cells, tissues, and organs.
• Somatic Mutation. Genetic mutations occur and accumulate with increasing age, causing cells to deteriorate and malfunction.

Both average life span and life expectancy in the United States have grown dramatically in the past century, from about 47 years in 1900 to about an average of 75 years in 1990.

This advance can be generally attributed to improvements in sanitation, the discovery of antibiotics, and medical care. Now, as scientists make headway against chronic diseases like cancer and heart disease, some think it can be extended even further.

One hundred and twenty two years, as far as we know, is the longest that anyone has ever lived. A woman in France, Jeanne Calment, reached the age of 122 years in 1997, according to details provided by her retirement home. No precise cause of death was recorded.

Those "blessed" with long lives always make us wonder: What is the secret? Does it lie in the genes? Is it where people live or the way they live -- something they do or do not do? Eat or do not eat?  Is the human lifespan something that with modern technology we can extend?

Did Jeanne Calment approach some built-in, biological limit? Is there a maximum human life span beyond which we cannot live no matter how optimal our environment or favorable our genes?

Whether or not there is such a limit, what happens as we age? What are the dynamics of this process and how do they make life spans short, average, or long? With an understanding of these dynamics, can we use this understanding to extend the human life span to 120 or even, as some scientists speculate, to much greater ages?

And finally, but potentially most importantly, how can insights into longevity be used to fight the diseases and disabilities associated with old age to make sure this period of life is healthy, active, and independent?

Produced by H.F.R.

Human Growth Hormone is one of several endocrine hormones, like estrogen, progesterone, testosterone and DHEA that decline in production as we age. While many of these hormones can be replaced to deter some of the effects of aging, growth hormone goes far beyond the effect of any one of these hormones to not only retard biological aging, but also to significantly reverse many of the effects of aging. Researchers have proven growth hormone therapy can reverse the biological effects of aging by as much as 20 years with less than one year of treatment.  Click 'Read More' Below

WILL GROWTH HORMONE PROVE TO BE THE FIRST ‘ANTI-AGING’ MEDICATION?

It is a fact that we are going to grow old. In fact, with the ‘baby boomer’ generation approaching their mid 50’s, the number of elderly Americans are substantially increasing. Then, why does it have to remain a fact that we will grow old in exactly the very same way our forefathers did before us: frail, confused, weak, fatigues, depressed, afraid to walk outdoors for fear of falling on the pavement?

There is an old adage that states that...... Youth is wasted on the young.
If this is true, why should it follow that experience and financial security are 'wasted on the old’ because they have lost the energy and enthusiasm to enjoy the 'golden years?'

This article describes growth hormone physiology, with brief mentions of the diseases of GH deficiency, GH excess (acromegaly and pituitary gigantism), as well as GH treatment. For information on a common growth hormone sometimes given to cows, see bovine somatotropin.