1. Nancy V. Karp, Ed.D., P.T. nvkarp@gmail.com
Theories of Aging
Nancy V. Karp, Ed.D., P.T.

2. Objectives
This presentation will describe aging from both a biological/physiological and a psychosocial perspective.
Biological/physiological theories will be presented in two main categories, program theories and error theories.
Psychosocial theories will be discussed in two main categories, full-life theories and mature-life theories.

3. Ponce De Leon In Search of the Fountain of Youth

5. Is There a Fountain of Youth?

6. Is There a Fountain of Youth?

7. What is Aging?
The gradual and spontaneous changes that occur in maturation from infant to young adult. These changes create a normal physiologic decline seen in middle and late adulthood.
Changes during puberty
Graying of hair

8. Senescence
The process by which a cell looses its ability to divide, grow, and function. This loss of function ultimately ends in death.
A degenerative process, only.
Has no positive features.

9. Normal vs. Healthy Aging
Normal Aging
Diseases & impairments of elderly
People age differently
Diabetes may be a common disease of adulthood, but is not experienced by all aging adults.
Healthy Aging
Minimize and preserve function
Influenced by lifestyle choices
One may have a healthy life until senescence makes life impossible.

10. Life Expectancy Some Factors Influencing Your Life Expectancy Heredity
Disease Processes
Medical Treatment
Lifestyle Choices
Nutrition

11. Theories of Aging
“The link between genes and lifespan is unquestioned. The simple observation that some species live longer than others -- humans longer than dogs, tortoises longer than mice -- is one convincing piece of evidence.”
The National Institute on Aging

12. Theories of Aging All aging begins with genetics
Aging changes the biochemical and physiological processes in the body
Cell and molecular biologists examine and propose theories to explain the aging process
What causes aging?
How can you influence aging …prolong life?

13. The Two Main Aging Theory Categories
Programmed Theories
Aging has a biological timetable or internal biological clock.
Error Theories
Aging is a result of internal or external assaults that damage cells or organs so they can no longer function properly.
Many theories are a combination of programmed and error theories.

14. Programmed vs. Error Theories
Programmed Theories
Programmed Senescence Theory
Endocrine Theory
Immunology Theory
Error Theories
Wear and Tear Theory
Rate-of-Living Theory
Cross-linking Theory
Free Radical Theory
Error CatastropheTheory
Somatic Mutation Theory

15. Programmed Senescence Theory Endocrine Theory Immunology Theory
Programmed Theories
Programmed Senescence Theory
Endocrine Theory
Immunology Theory

16. Programmed Senescence Theory
The result of sequential switching “off” or “on” of specific genes.
Example – “Hayflick’s Limits”
Fibroblasts removed from umbilical cord & cultured
Fibroblasts divide and repeated until ~ 50 divisions
Will not divide past this point

17. Telomeric Theory This is an extension of the “Hayflick Limit.”
Telomeres are specialized DNA sequences at the end of chromosomes.
They shorten with each cell division.
When the telomeres become too short, the cell enters the senescence stage.
In the normal process of DNA replication, the end of the chromosome is not copied exactly, which leaves an unreplicated gap.

19. Telomeric Theory
The enzyme, telomerase, fills the gap by attaching bases to the end of the chromosomes.
As long as the cells have enough telomerase to do the job, they keep the telomeres long enough to prevent any important information from being lost as they go through each replication.
With time, telomerase levels decrease.
With decreasing telomerase levels, the telomeres become shorter and shorter.

21. Telomeric Theory Shortened telomeres are found in: Atherosclerosis
Heart disease
Hepatitis
Cirrhosis

22. Telomeric Theory and Cancer
90% of cancer cells have been found to possess telomerase.
Telomerase prevents the telomere from shortening.
This allows the cancer cells to reproduce, resulting in tumor growth.
Research areas
Measuring telomerase may help detect cancer.
Stopping telomerase may fight cancer by causing death of cancer cells.
Telomerase may be used to help with wound healing or the immune response.

23. 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

24. Immunologic Theory
A programmed decline in the immune system leads to an increased vulnerability to disease, aging and death
Example- Decreased T cells (helper cells) in adults
Increased diseases in older adults
Increased autoimmune diseases in adults

25. Error Theories Wear and Tear Theory Error Free Radical Theory
Rate-of-Living Theory CatastropheTheory
Cross-linking Theory Somatic Mutation Theory

26. 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.

27. Rate-of-Living Theory
The greater an organism’s basal metabolic rate, the shorter the life span.
Free radicals or other metabolic by-products play a role in senesce.
Example
Animals with the most rapid metabolisms tend to have the shortest lifespans, i.e, birds have a shorter lifespan than humans.
Studies examining the relationship between metabolic rates and longevity have produced inconsistent results, limiting the usefulness of this theory.

28. 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

29. 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.

31. 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.

32. 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.

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

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

35. 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.

36. 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.

37. repaired
membrane
anti-oxidant
molecule
damaged
DNA
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.

38. 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.

39. 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?

40. Can This Stop Aging?

41. Can you delay or stop aging by taking vitamins and other free radical scavengers?
There is no evidence-based proof that dietary supplements delay or stop aging. This is a big area of nutrition quackery. BEWARE!
Remember, there is a lot of evidence-based proof that taking some supplements INCREASES cancer rate, for example lung cancer. Smokers who take beta-carotene supplements have higher lung cancer rates than smokers not taking these supplements.
Therefore, the risk/benefit ratio is in favor of NOT taking SUPPLEMENTS to retard aging.

42. Catastrophe Theory
Any damage to the enzyme systems that synthesize proteins in the body results in faulty protein synthesis.
The faulty proteins continue to accumulate in the cell until they reach a level that damages the cells, tissues, and organ
When enough damage accumulates, this may result in cell malfunctioning ( aging) leading to death.

43. Somatic Mutation
Genetic mutations occur and accumulate with age in the somatic cell causing the cell to:
Deteriorate
Malfunction
Accumulation of mutations result in :
Damage to the DNA
The theory states that aging is an imbalance between DNA’s ability to repair itself and accumulating DNA damage.
When the damage exceeds the repair, the cell malfunctions and this can lead to senesence.

44. Psychological Theories of Aging

45. Psychological Theories of Aging
Full-Life Development Theories (Erikson’s Theory will be the only one discussed.)
Mature-Life Theories
Robert Peck’s Theory
The Activity Theory (Neugarten’s Theory will be the only one discussed.)
The General Theory of Disengagement

46. Full-Life Development Theory
Eric Erickson was one of the first psychological theorists to develop a personality theory that extends to old age.

47. Full-Life Development Theory Major Concepts
The ego is a positive driving force for development.
The ego’s job is to establish and maintain identity.
A lack of identify leads to lack of direction and non-productivity.
There are stages of personality and ego development.

48. Full-Life Development Theory Major Concepts
The last stages are “Adulthood” & “Late Life Stage.”
“Adulthood” is characterized by a struggle between “Generativitiy” and Stagnation.
“Generativity”
Giving back to society by raising children
Being productive at work
Being involved in the community
Guiding, parenting, and monitoring the next generation

49. Full-Life Development Theory Major Concepts
Stagnation
Being unproductive
Feeling anger, hurt and self absorption
As one becomes mature, there is a struggle between “Ego Integrity” & despair
“Ego Integrity”
Exploring life as a retired person who is not identified with an occupation
Contemplating accomplishment
Feeling life is successful

50. Full-Life Development Theory
Despair
Feeling guilt about the past
Not accomplishing life goals
The final pathway:
dissatisfied despair
depression hopelessness

51. Mature-Life Theories

52. Mature-Life Theories Robert Peck
The elderly go through three developmental stages to reach full psychosocial development.
Stage 1 - Ego Differentiation vs. Work Role Preoccupation
Stage 2 - Body Transcendance vs. Body Preoccupation
Stage 3 - Ego Transcendance vs. Ego Preoccupation

53. Stage 1 Ego Differentiation vs. Work Role Preoccupation
As a person matures, that person moves from “Work Role Preoccupation” which is a concept that describes defining oneself through work or an occupation.
A person finds new meaning and value in his or her life. This process is called “Ego Differentiation.”

54. Stage 2 Body Transcendance vs. Body Pre-occupation
A person either accepts the limitations that accompanies the aging process (Body Transcendance) or dwells on diminishing abilities (Body Pre-occupation).

55. Stage 3 Ego Transcendance vs. Ego Preoccupation
Self-examination occurs.
If a person believes his or her life has worth and “life contributions” will live on after death, the person experiences “Ego Transcendence.”
Otherwise, the person may feel that he or she has lived a useless life and experience “Ego Preoccupation.”

56. Mature-Life Theories Neugarten
Bernice Neugarten describes tasks that must be accomplished for successful aging. Some of these tasks include:
Accepting reality and the imminence of death.
Coping with physical illness.
Accepting the necessity of being dependent on outside support while still making independent choices that can give satisfaction.

57. Mature-Life Theories Neugarten
A person must remain as active as possible. This falls under the category of “activity theory.”

58. Mature-Life Theories General Theory of Disengagement
This theory is controversial and has these features:
Both older people and society mutually withdraw from each other.
A person gradually disconnects from other people in anticipation of death.
Intrinsic changes in personality occur which allow a person to psychologically withdraw from society’s expectations.
Note: This is the opposite of “Activity Theory.”

59. Summary
This presentation has described aging from both a biological/physiological and a psychosocial perspective.
Biological/physiological theories are divided into two main categories, program theories and error theories.
Psychosocial theories are divided into two main categories, full life theories and mature life theories.

60. The End