The document discusses several theories of aging from biological and sociological perspectives. Biologically, aging is influenced by both genetic and environmental factors. Stochastic theories propose aging results from random damage caused by free radicals and errors over time. Non-stochastic theories view aging as programmed by genes or hormones. Sociologically, theories examine how social engagement or disengagement impact aging, as well as the influence of social roles and status. Psychologically, theories explore how human needs, personality development, and life stages shape aging. The document provides examples and details for numerous theories of biological, sociological, and psychological aging.

1. Theories of Aging
Dr. Ramandeep Kaur Saini (PT)
Assistant Professor-Community Physiotherapy
DPO’s NETT College of Physiotherapy

2. Objectives:
At the end of this session you will be able to-
• Define aging
• Identify different theories of aging
• Describe the theories of aging using biological and non-biological
perspective

3. What is aging?
• Aging is the accumulation of changes in an organism overtime or latter
part of animate life.
• Multidimensional process

4. What is aging?
• Aging is the deterioration of a mature organism resulting from time dependent,
essentially irreversible changes intrinsic to all members of the species such that with the
passage of time they become increasingly unable to cope with stresses of environment,
thereby increasing the probability of death. (Handler)

5. Types of aging
Biological
Psychological
Functional
Social
Reference: Pathath A W (2017), Theories of Aging, International Journal of Indian Psychology, Volume 4, (3)

6. Theories of aging: types

7. Biological aging
• Age associated changes that involve physical structure and functioning of body
affecting persons ability to function or survive.
• Regulated by 2 factors- a genetic component
- environmental and lifestyle component
• Biological aging theories:
Stochastic
Non
Stochastic

8. Foci of Biological Theories
• Explanations of:
1) deleterious effects leading to decreasing
function of the organism
2) gradually occurring age-related changes
that are progressive over time
3) intrinsic changes that can affect all member
of a species because of chronologic age
Reference: Madison, H.E. (2002).“Theories of Aging”. In Lueckenotte, A.G. (ed), Gerontologic Nursing. St. Louis: Mosby.

9. STOCHASTIC THEORIES NON-STOCHASTIC THEORIES
FREE RADICAL PROGRAMMMED
ERROR/ORGEL GENE/BIOLOGICAL CLOCK
WEAR AND TEAR NON-ENDOCRINE
CROSS LINKAGE THEORY IMMUNOLOGICAL
WASTE ACCUMUATION THEORY
SOMATIC MUTATION THEORY
Biological aging

10. Stochastic theories-
Free radical theory
• Oxidation of protein, fat, & carbohydrate results in free radical formation.
• This theory suggest that highly reactive by-product of oxidative metabolism can react with cellular constituent
including proteins, DNA, lipids, to generate long-lived dysfunctional molecules that interfere with cellular
function.
• Plasma membrane damage by free radical which is essential for homeostasis.

11. Oxidation of proteins,
fat and carbohydrate
results in free radical
formation
Free radicals react with
cellular constituents and
generate dysfunctional
molecules.
Dysfunctional molecules
interfere with cellular
function.
Cellular function alters
essential organ function.
Anitoxidants (Vit A,C,E
) are free-radical
scavengers, providing
high levels of protection
against free radicals.

12. Free Radical Theory- Effect on
cellular components
Plasma
• Poor homeostasis
• Initiate
inflammation
• Excess blood
clotting
• Promotes
diseases
DNA
• Inability to
produce adequate
energy.
• Impacts skeletal
muscle strength
and endurance
Proteins
• Limit joint ROM
• Increased
tendency to form
adhesions in
tendons and
ligaments

13. Error theory
• Over time, cells accumulate errors in their DNA and RNA protein synthesis that
cause the cells to die (Orgel, 1970).
• Environmental agents and randomly induced events can cause error, with ultimate
cellular changes.
• Aging would not occur if destructive factors did not exist and cause ‘errors’ such
as mutations and regulatory disorders.
• Example- Large amounts of X-ray radiation, UV radiation cause chromosomal
abnormalities.

14. Wear and tear theory
• The daily grind of life, in particular abuse or overuse, literally wears the body out, leading to disease states.
• Example- The degeneration of cartilage and eventual grinding of bone on bone causes aging process, as wear and tear
exceeds the body’s ability to repair.
• Cells in heart muscle, neurons, striated muscle, and the brain cannot replace themselves
after they are destroyed by wear and tear.
• Studies of people with osteoarthritis suggest that cartilage cells age over time, and this
degeneration is not due solely to strenuous exercise but also to general wear and tear.
• These studies point out that aged cells have lost the ability to counteract mechanical, inflammatory, and other injuries due
to their senescence (Aigner, Rose, Martin, & Buckwalter, 2004).

15. Cross linkage theory
• Over time, biochemical processes create connections between structures not normally
connected.
• With age, collage is less soluble, rigid and cross-linked.
• Molecular cross linking between protein molecules such as collagen found in skin, tendons &
ligaments and the glycation (cross linking) of other structural proteins & lipids(fats) with
excess glucose disrupts the functions of these molecules, leading to acceleration of ageing
process.
• Example- Elastin dries up and cracks with age. Hence skin with less elastin tends to be drier
and wrinkled.
• Over time, because of decreased extracellular fluid, numerous deposits of sodium, chloride,
and calcium build up in the cardiovascular system.

16. • Waste accumulation theory
• The somatic mutation theory of aging

17. Non stochastic:
Programmed theory
• The Hayflick phenomenon suggests that cells divide
until they can no longer divide, whereupon the cell’s infrastructure
recognizes this inability to further divide and triggers the apoptosis sequence or death of the
cell.
• Human cells age each time they replicate because of the shortening of the telomere.
• Example- Increased cell apoptosis rates cause organ dysfunction, and this is hypothesized to
be the underlying basis of the pathophysiology of multiple organ dysfunction syndrome.

18. Gene / Biological clock theory
• Each cell, or perhaps the entire organism, has a genetically programmed aging code that is stored in the organism’s DNA.
• Slagboom and associates describe this theory as comprising genetic influences that predict physical condition, occurrence
of disease, cause and age of death, and other factors that contribute to longevity.
• Example- everyday rhythm of the cycle of sleep–wake cycle intervals is part of a time-keeping framework created by an
internal clock of body. Its thought that biological rhythm lose some rhythmicity with aging.
• Because of the linkage with the hypothalamus, autonomic nervous system, and brain stem reticular formation, diurnal
changes in metabolism, body temperature, and heart rate and blood pressure occurs.

19. Neuroendocrine theory
• This theory describes a change in hormone secretion. When the stimulating and releasing hormones of the pituitary
and the hypothalamus are out of synch with the endocrine glands, an increase in disease is expected in multiple
organs and systems
• Examples- Decreased estrogen causes the thinning of bones in older women.
• Growth hormone is part of the process that increases bone and muscle strength. GH stimulated the release of insulin
like growth factor produced by liver.
• Melatonin is produced by the pineal gland and is thought to be responsible for coordinating seasonal adaptations in
the body.
• There is a higher chance of excess or loss of glucocorticoids, aldosterone, androgens, thyroxine, and parathyroid
hormone when the hypothalamus pituitary- endocrine gland feedback system is altered.

20. Immunological theory
• Describes the normal aging process of humans and
animals as being related to faulty immunological
function (Effros, 2004).
• Example- Decreased immune function in the elderly due
to the thymus gland shrinking to 15% of its capacity,
• Altered lymphocyte function-T cell differentiation lost
with aging
• Decreased cell mediated and humoral immune response

21. Summary of biological theories:

22. Sociological theories of aging
1. Activity theory
2. Disengagement theory
3. Selectivity theory
4. Subculture theory
5. Age stratification theory
6. Continuity theory

23. Activity theory
• Individuals need to remain active to age successfully.
• Activity is necessary to maintain life satisfaction and a
positive self-concept
• As role changes, individual finds substitute activity for the
same.

24. Disengagement theory
• Proposed by Cumming and Henry.
• As individuals age, they withdraw from society, and society encourages this withdrawal.
• Individuals would change from being centered on society and interacting in the community to
being self-centered persons withdrawing from society, by virtue of becoming “old.”
• Social equilibrium would be the end result.

25. Selectivity theory
• Mediates between activity and disengagement theory
• May benefit older people to become more active in some aspects of their lives
while more disengaged in others.

26. Continuity theory
• Atchley’s theory that in later life the elders make adaptations to enable
them to gain a sense of continuity between past and present.
• Inclined to maintain habits, personalities and life-styles
• Contributes to well being

27. Subculture
• Older adults form a unique subculture within society to defend against
society’s negative attitude towards aging and accompanying loss in
status.
• Social status determined by health and mobility (Rose,1965)

28. Age stratification
• Rileys and colleagues observed that society is stratified into
different age categories that are the basis for acquiring
resources, roles, status and deference from others in society.
• People born in same cohort has same ideologies, experiences,
attitudes and values as well as expectations regarding the
timing of life transitions.
• Thus, there is a high degree of interdependence between older
adults & society

29. Summary of social theories:

30. Psychological theories
1. Human needs
2. Individualism
3. Life span
4. Stages of personality development

31. Human needs
• Maslow--1954
• Each individual has an innate
internal hierarchy of needs that
motivates all human behaviors.
• depicted as a pyramid; the ideal is
to achieve self-actualization,
having met all the “lower” level
needs successful.

32. Individualism
• Jung's theory,1960
• Our personality develops over a life time and is composed of an ego
or self identity that has personal and collective unconsciousness.
• As individual age, they begin to reflect on their beliefs and life
accomplishments.
• One age successfully when he or she accepts the past, adapts to
physical decline and cope with the loss of significant others.

33. Life course
• Life stages are predictable and structured by roles, relationships and
values, development and goals.
• Person adapt to changing roles and relationship.
• Age-group norms and characteristics are an important part of the life
course.

34. Stages of personality
development
• Erikson’s theory
• 8 sequential stages of personality development
• Ego integrity versus despair
• Individual search for meaning of their lives and
evaluate accomplishments
• Older adults face additional challenge or life tasks
including physical and mental decline
• Accepting the care of others and detachment

35. Summary of psychological
theories:

36. References
1. Jean Lange,Theories Of Aging. The Gerontological Nursing Competences For
Care.2nd ed.
2. Physiotherapy in Community Health And Rehabilitation, Waqar N.
3. Pathan AW, Theories of Aging, The Int J. Of Indian Psychology,2017.
4. Madison, H.E. (2002).“Theories of Aging”. In Lueckenotte, A.G., Gerontologic
Nursing.

37. THANK YOU