https://physioaadhar.com/physiotherapy-blogs/ These two categories of the theory are also referred to as non-programmed ageing theories based on evolutionary concepts (where ageing is considered the result of an organism's inability to better combat natural deteriorative processes), and programmed ageing theories (which consider ageing to ultimately be the result o

1. Theories of Aging

2. “Everyman desires to live long, but
no man would be old.”
Johnathan Swift, 1667-1745

3. Theories of Aging
Biological Theories
 address the anatomic and physiologic
changes occurring with age.
Psycho-Social Theories
 explain the thought processes and behaviors
of aging persons.

4. Biological Theories of
Aging
Genetic
Theories
 Gene
 Error
 Somatic mutation
 Programmed
Nongenetic
Theories
 Immunologic /
Autoimmune
 Free Radical
 Wear & Tear
 Cross link or Collagen

5. Endocrine Theory
 Biological clocks act through hormones to
control the pace of aging. Hormones
effects growth, metabolism, temperature,
inflammation and stress.
 Examples- Menopause
◦ Decreased level of estrogen & progesterone
◦ Hot flashes, insomnia

6. Wear and Tear Theory
 Years of damage to cells, tissues and
organs eventually wears them out, killing
both them and the body
 Example- Wearing out of the skeletal
system such as in osteoarthritis
 Wear and tear can be viewed as a result
of aging and not the cause of it.

7. Cross-Linking Theory
 The accumulation of cross-linked
proteins damages cells and tissue,
slowing down bodily processes.
 Example
Non-enzymatic glycosylation reactions
occur when glucose molecules attach to
proteins causing a chain of chemical
reactions resulting in a structural
change to the proteins.
◦ Loss of flexibility of connective tissue
◦ Microvascular changes in arteries

8. Free Radical Theory
 During aging, damage produced by free
radicals cause cells and organs to stop
functioning.
 A free radical is a molecule with an unpaired,
highly reactive electron. One type of very
reactive free radical is the oxygen free
radical, which may be produced during
metabolism or as a result of environmental
pollution.
Oxygen free radicals are formed in your cells,
naturally, during the oxidation of food to water and
carbon dioxide.

10. Free Radical Theory
The free radical “grabs” a electron from
any molecule it its vicinity.
It does this because electrons like to exist
in pairs.
When it “grabs” an electron from another
molecule, it damages the other molecule.

11. Free Radical Theory
 Some of the molecules that may be damaged
by free radicals are fats, proteins, and DNA
(both in the nucleus and in mitochondria).
 If membrane fats are attacked, then you get
the breakdown of the cell membrane. If it is a
red blood cell membrane, you get hemolysis.
 If proteins are attacked, you get the
breakdown of proteins, which may result in
the loss of biological function and the
accumulation of “catastrophic” compounds.
 If DNA is attacked, you will get a mutation
that may cause aging or cancer.

12. Free Radicals
As the free radical (green) attacks the membrane it
can release another type free radical (blue).

13. Damaged membrane
The free radical (blue) attacks the DNA releasing another
free radical (purple).
mitochondrion

14. Free Radical Theory
 Free radicals do not go unchecked. The
body has a multi-layed defense system
that reacts and detoxifies the damaging
radicals.
 Defenses include:
◦ Natural antioxidants in the body, such as
bilirubin.
◦ Enzymes such as superoxide dismutase (SOD),
catalase, & glutathione peroxidase.
◦ Dietary antioxidants such as beta carotene,
and the vitamins C and E.

15. Free Radical Theory
 Under normal conditions, your natural
defense mechanisms prevent most of the
oxidative damage from occurring.
 The free radical theory of aging proposes
that, little-by-little, small amounts of
damage accumulate and contribute to
deterioration of tissues and organs.

16. The anti-oxidant molecule destroys the damaging free radical. The
membrane repairs itself, but the DNA remains damaged, impairing the
cells function. In addition, the anti-oxidant molecule now has an
unpaired electron and thus becomes a new radical.
anti-oxidant
molecule
repaired
membrane
damaged
DNA

17. Free Radical Theory
For example, when Vitamin E “scavenges”
free radicals, it becomes a free radical and
may be more carcinogenic than the
original free radical.
This is the reason why taking high doses
of vitamin E SUPPLEMENTS appears to
INCREASE cancer risk in a person, not
decrease cancer risk.

18. Free Radical Theory
 Not all free radicals cause damage.
 You use free radicals as part of your
immunological response system.
◦ Macrophages engulf bacteria
◦ Free radical reactions produced inside the
macrophage oxidize and kill bacteria.
Question: Does it make any biological sense to
try to eliminate all free radicals in your body by
taking supplements?

19. Psycho-Social Theories of Aging
 Disengagement
Theory
 Activity Theory
 Continuity Theory

20. Disengagement
Theory
 developed by Cummings and Henry in late
1950’s.
 “aging is an inevitable, mutual withdrawal
or disengagement, resulting in decreased
interaction between the aging person and
others in the social system he/she belongs
to.”

21. Activity Theory
 developed by Robert Havighurst in the 1960’s.
 supports the maintenance of regular activities,
roles, and social pursuits.
 persons who achieve optimal age are those who
stay active.
 as roles change, the individual finds substitute
activities for these roles.

22. Continuity Theory
 proposed by Havighurst and co-workers in
reaction to the disengagement theory
 “basic personality, attitudes, and behaviors
remain constant throughout the life span”

23. “ENJOY THE BALLET, LORETTA ….AND TRY TO SELL MY TICKET.”

24. Thanks!!