THEORIES OF AGING

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THEORIES OF AGING

• Based on information in Madison, H.E.
  (2002).Theories of Aging. In Lueckenotte, A.G.
  (ed), Gerontologic Nursing. St. Louis Mosby.

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• Theories of Aging
• attempt to explain the phenomenon of aging as it
  occurs over the lifespan
• aging is viewed as a total process that begins at
  conception
• senescence a change in the behavior of an
  organism with age leading to a decreased power of
  survival and adjustment

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Theories of Aging Types

• Biologic
• Sociologic
• Psychologic
• Moral/Spiritual

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Biologic Theories

• Concerned with answering basic questions
  regarding the physiological processes that occur
  in all living organisms as they chronologically
  age

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Foci of Biologic 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

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• ALSO
• all organs in any one organism do not age at the
  same rate
• any single organ does not necessarily age at the
  same rate in difference individuals of the same
  species

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Biologic Theories Divisions

• Stochastic Explain aging as events that occur
  randomly and accumulate over time
• Nonstochastic View aging as certain
  predetermined, timed phenomena

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• Stochastic Theories
• Error Theory Free Radical Theory
• Cross-Linkage Theory
• Wear Tear Theory

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Error Theory

• Originally proposed in 1963
• Basis 1)errors can occur in the transcription in
  any step of the protein synthesis of DNA
• 2) error causes the reproduction of an enzyme or
  protein that is not an exact copy
• 3) As transcription errors to occur, the end
  product would not even resemble the original
  cell, thereby compromising its functional ability

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Error, contd

• More recently the theory has not been supported
  by research
• not all aged cells contain altered or
  misspecified proteins
• nor is aging automatically or necessarily
  accelerated if misspecified proteins or enzymes
  are introduced into a cell

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Free Radical Theory

• Free radicals are byproducts of metabolism--can
  increase as a result of environmental pollutants
• When they accumulate, they damage cell membrane,
  decreasing its efficiency
• The body produces antioxidants that scavenge the
  free radicals

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Free Rads, contd

• In animal studies, administration of antioxidants
  postpones the appearance of diseases such as
  cardiovascular disease and CA
• Free radicals are also implicated in the
  development of plaques associated with Alzheimers

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Cross-Linkage Theory

• Some proteins in the body become cross-linked,
  thereby not allowing for normal metabolic
  activities
• Waste products accumulate
• Result tissues do not function at optimal
  efficiency

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C-L Theory, contd

• Some research supports a combination of exercise
  and dietary restrictions in helping to inhibit
  the cross-linkage process

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Wear Tear Theory

• Proposed first in 1882
• Cells simply wear out over time because of
  continued use--rather like a machine
• Would seem to be refuted by the fact that
  exercise in OAs actually makes them MORE
  functional, not less

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• Nonstochastic Theories
• Programmed Theory
• Immunity Theory

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Programmed (Hayflick Limit) Theory

• Based on lab experiments on fetal fibroblastic
  cells and their reproductive capabilities in 1961
• Cells can only reproduce themselves a limited
  number of times.
• Life expectancies are seen as preprogrammed
  within a species-specific range

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Immunity Theory

• Immunosenescence Age-related functional
  diminution of the immune system
• Lower rate of T-lymphocyte (killer cells)
  proliferation in response to a stimulus
• therefore a decrease in the bodys defense
  against foreign pathogens

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Immunity, contd

• Change include a decrease in humoral immune
  response, often predisposing older adults to
• 1)decreased resistance to a tumor cell challenge
  and the development of cancer
• 2) decreased ability to initiate the immune
  process and mobilize defenses in aggressively
  attaching pathogens
• 3) increased susceptibility to auto-immune
  diseases

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EMERGING THEORIES OF AGING

• Neuroendocrine Control (Pacemaker) Theory
• Metabolic Theory/Caloric Restriction
• DNA-Related Research

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Neuroendocrine Control

• examines the interrelated role of the
  neurologic and endocrine systems over the
  life-span of an individual. (p. 24)
• there is a decline, or even cessation, in many of
  the components of the neuroendocrine system over
  the lifespan

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Neuro, contd

• Research has shown
• 1) the female reproductive system is controlled
  by the hypothalamus. What are the mechanisms
  that trigger changes?
• 2) adrenal glands DHEA hormone
• 3) melatonin (from pineal gland)--a regulator of
  biologic rhythms and a powerful antioxidant.
  Declines sharply from just after puberty

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Metobolic Theory of Aging (Caloric Restriction)

• proposes that all organisms have a finite
  amount of metabolic lifetime and that organisms
  with a higher metabolic rate have a shorter
  lifespan. (p. 24)
• Rodent-based research has demonstrated that
  caloric restriction increases the lifespan and
  delays the onset of age-dependent diseases

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DNA-Related Research

• Major Developments
• Mapping the human genome (there may be as many
  as 200 genes responsible for contolling aging in
  humans)
• Discovery of telomeres

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SOCIOLOGIC THEORIES OF AGING

• Disengagement Theory
• Activity/Developmental Task Theory
• Continuity Theory
• Age Stratification Theory
• Person-Environment Fit Theory

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• Changing FOCUS of Sociological considerations of
  aging
• 60s focus on losses and adaptation to them
• 70s broader global, societal, and structural
  factors influencing lives of OAs
• 80s-90s exploration of interrelationships
  between OAs and their physical, political,
  environmental socioeconomic mileau

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Disengagement Theory

• Cumming Henry--1961
• Aging seen as a developmental task in and of
  itself, with its own norms appropriate patterns
  of behavior
• appropriate behavior patterns involved a mutual
  agreement between OAs and society on a
  reciprocal withdrawal.
• No longer supported

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Activity Theory (Developmental Task Theory)

• Havighurst, Neugarten, Tobin 1963
• Activity is viewed by this theory as necessary
  to maintain a persons life satisfaction and a
  positive self-concept. (p.27)

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Activity, contd

• Theory based on assumptions
• 1) its better to be active than inactive
• 2) it is better to be happy than unhappy
• 3) an older individual is the best judge of his
  or her own success in achieving the first two
  assumptions

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Continuity Theory

• How a person has been throughout life is how that
  person will continue through the remainder of
  life
• Old age is not a separate phase of life, but
  rather a continuation and thus an integral
  component

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Age Stratification Theory

• Riley--1985
• Society consists of groups of cohorts that age
  collectively
• The people Roles in these cohorts change
  influence each other, as does society at large
• Thus, there is a high degree of interdependence
  between older adults society

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Person-Environment Fit Theory

• Lawton, 1982
• Individuals have personal competencies that
  assist in dealing with the environment
• ego strength
• level of motor skills
• individual biologic health
• cognitive sensory-perceptual capacities

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P-E Fit, contd

• As a person ages, there may be changes in
  competencies these changes alter the ability to
  interrelate with the environment
• Significant implications in a society that is
  characterized by constantly changing technology

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PSYCHOLOGIC THEORIES OF AGING

• Maslows Hierarchy of Human Needs
• Jungs Theory of Individualism
• Eriksons Eight Stages of Life
• Pecks Expansion of Eriksons Theory
• Selective Optimization with Compensation

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Maslows Hierarchy of Human Needs

• Maslow--1954
• each individual has an innate internal
  hierarchy of needs that motivates all human
  behaviors. (p. 29
• depicted as a pyramid the ideal is to achieve
  self-actualization, having met all the lower
  level needs successful

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• Maslows fully developed, self-actualized person
  displays high levels of all of the following
  characteristics perception of reality
  acceptance of self, others, and nature
  spontaneity problem-solving ability
  self-direction detachment and the desire for
  primacy freshness of peak experiences
  identification with other human beings.

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• satisfying and changing relationships with other
  people a democratic character structure
  creativity and a sense of values.
• Only about 1 of us are truly ideal
  self-actualized persons

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Jungs Theory of Individualism

• Carl Jung--1960
• origins are Freudian
• Self-realization is the goal of personality
  development
• as individual ages, each is capable of
  transforming into a more spiritual being

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Eriksons Eight Stages of Life

• 1993
• Stages throughout the life course. Each
  represents a crisis to be resolved.
• For OAs
• 40 to 65 (middle adulthood) generativity versus
  self-absorption or stagnation
• 65 to death (older adulthood) ego integrity
  versus despair

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Erikson, contd

• Self-absorbed adults will be preoccupied with
  their personal well-being and material gains.
  Preoccupation with self leads to stagnation of
  life
• Unsuccessful resolution of the last crisis may
  result in a sense of despair in which individuals
  view life as a series of misfortunes,
  disappointments, and failures. (p.30)

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Pecks Expansion of Eriksons Theory

• Eriksons last two stages are expanded to 7
• The final three of the developmental tasks for
  old age
• ego differentiation versus work role
  preoccupation
• body transcendence versus body preoccupation
• ego transcendence versus ego preoccupation

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Selective Optimization with Compensation

• Baltes--1987
• Individuals develop strategies to manage losses
  of function that occur over time

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Selective Optimization, contd

• 3 Interacting Elements
• selection increasing restriction of ones life
  to fewer domains of functioning
• optimization people engage in behaviors to
  enrich their lives
• compensationdeveloping suitable, alternative
  adaptations

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THE END!

• Thanks for hanging in there!