THEORIES OF AGING Based on information in Madison

THEORIES OF AGING Based on information in: Madison, H. E. (2002). “Theories of Aging”. In Lueckenotte, A. G. (ed), Gerontologic Nursing. St. Louis: Mosby.

¬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

Theories of Aging: Types ¬Biologic ¬Sociologic ¬Psychologic ¬Moral/Spiritual

Biologic Theories: ¬Concerned with answering basic questions regarding the physiological processes that occur in all living organisms as they chronologically age

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

¬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

Biologic Theories: Divisions ¬Stochastic: Explain aging as events that occur randomly and accumulate over time ¬Nonstochastic: View aging as certain predetermined, timed phenomena

¬Stochastic Theories ¬Error Theory Free Radical Theory ¬Cross-Linkage Theory ¬Wear & Tear Theory

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

Error, cont’d ¬More recently 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

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

Free Rads, cont’d ¬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 Alzheimer’s

Cross-Linkage Theory ¬Some proteins in the body become crosslinked, thereby not allowing for normal metabolic activities ¬Waste products accumulate ¬Result: tissues do not function at optimal efficiency

C-L Theory, cont’d ¬Some research supports a combination of exercise and dietary restrictions in helping to inhibit the cross-linkage process

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 OA’s actually makes them MORE functional, not less

¬Nonstochastic Theories: ¬Programmed Theory ¬Immunity Theory

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

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 body’s defense against foreign pathogens

Immunity, cont’d ¬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

EMERGING THEORIES OF AGING ¬Neuroendocrine Control (Pacemaker) Theory ¬Metabolic Theory/Caloric Restriction ¬DNA-Related Research

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

Neuro, cont’d ¬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

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 agedependent diseases

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

SOCIOLOGIC THEORIES OF AGING ¬Disengagement Theory ¬Activity/Developmental Task Theory ¬Continuity Theory ¬Age Stratification Theory ¬Person-Environment Fit Theory

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

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 OA’s and society on a reciprocal withdrawal. ¬No longer supported

Activity Theory (Developmental Task Theory) ¬Havighurst, Neugarten, Tobin ~1963 ¬“Activity is viewed by this theory as necessary to maintain a person’s life satisfaction and a positive self-concept”. (p. 27)

Activity, cont’d ¬Theory based on assumptions: – 1) it’s 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

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

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

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

P-E Fit, cont’d ¬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

PSYCHOLOGIC THEORIES OF AGING ¬Maslow’s Hierarchy of Human Needs ¬Jung’s Theory of Individualism ¬Erikson’s Eight Stages of Life ¬Peck’s Expansion of Erikson’s Theory ¬Selective Optimization with Compensation

Maslow’s 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

¬“Maslow’s 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; …….

¬…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 selfactualized persons

Jung’s 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

Erikson’s Eight Stages of Life ¬ 1993 ¬Stages throughout the life course. Each represents a crisis to be resolved. ¬For OA’s: – 40 to 65 (middle adulthood): generativity versus self-absorption or stagnation – 65 to death (older adulthood): ego integrity versus despair

Erikson, cont’d ¬“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)

Peck’s Expansion of Erikson’s Theory ¬Erikson’s 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

Selective Optimization with Compensation ¬Baltes--1987 ¬Individuals develop strategies to manage losses of function that occur over time

Selective Optimization, cont’d ¬ 3 Interacting Elements: – selection: increasing restriction of one’s life to fewer domains of functioning – optimization: people engage in behaviors to enrich their lives – compensation: developing suitable, alternative adaptations

THE END! ¬Thanks for hanging in there!