Gerontology is the study of aging.  Fairly new to scientific studies.  Yet much is coming to everyone’s knowledge about how we go into this process.  There are many theories about aging.  One group theorizes that aging is a natural and programmed process within our physiological changes.  An accumulation of damage over time.  Another theory believes that aging is a result of a complex interaction of genetics, chemistry, physiology and behavior.

Through in-depth understanding scientists are piecing the puzzle together.  Trial and error theories.  Studies have demonstrated that genetics can play a major role in aging.  When researchers adjust the genes in certain mice, yeast cells and other organisms, they can almost double the lifespan of these creatures.  The meaning of these experiments for people isn’t know just yet, but getting closer.  Researchers think that genetics account for up to 35 percent of the variation in aging among people.  Longevity genes indicate which person will live longer than others.  Cell senescence is the process by which cells deteriorate over time.  Telomeres result in the cells ceasing to replicate.  Stem cells can become any type of cell in the body and hold promise to repair damage caused by aging.

No matter what genes you inherited, your body is continually undergoing complex reactions.  Some of these reactions cause damage and, ultimately, aging in the body.  Studying these complex reactions is helping researchers understand how the body changes as it ages.  Important concepts in the biochemistry of aging include free radicals.  An unstable oxygen molecule can damage cells.  Antioxidant supplements can help clean up this process.  Protein cross-linking is caused by excess sugars in the blood stream which can cause protein molecules to literally stick together, causing more damage.  The body’s hormones change as we age, causing many shifts in organ systems and other functions.  Bioidentical hormone replacement is available.

The heart muscle thickens with age as a response to the thickening of the arteries.  The thicker heart has a lower maximum pumping rate.  Exercising is very important to delay this process.
Immune system aging is where the T cells take longer to replenish in older people and their ability to function declines.  The maximum capacity of the lungs may decrease as much as 40 percent between ages 20 and 70.

The brain ages due to hormonal changes and connections between neurons which seem to be reduced or less efficient.  This is not yet well understood.

Once again muscle tone declines about 22 percent by age 70, although exercise can slow this decline and is critical to many of the aging factors.

Kidneys become less efficient at cleaning waste from the body.  The total capacity of the bladder declines and tissues may atrophy, causing incontinence.  Special exercises can prevent this.
The good news is that many of these causes of aging can be modified through behavior changes.

REFERENCES:
Longevity.about.com.
www.who.int/mediacentre/factsheets