[GERON] Common Aging Changes - Theories of Aging

Living

a process of continual change

human aging

• influenced by a composite of biological, psychological, social, functional, and spiritual factors

• viewed as a total process that begins at conception

aging

may be viewed as a continuum of events that occur from conception to death

Biologic

concerned with answering basic questions regarding physiologic processes that occur in all living organisms over time

Sociologic

focused on the roles and relationships within which individuals engage in later life

Psychologic

influenced by both biology and sociology and addresses how a person responds to the tasks of their age

moral/spiritual

examine how an individual seeks to explain and validate their existence

Program Theory

• People inherit a genetic program that determines their specific life expectancy

• It proposed that animals and humans are born with a genetic program or biological clock that predetermines life span

• Various studies support this idea of a predetermined genetic program for life span

Error Theory

• Proposes a genetic determination for aging.

• This theory holds that genetic mutations are responsible for aging by causing organ decline as a result of self perpetuating cellular mutations:

Cross-Linking Theory

• proposes that cellular division is threatened as a result of radiation or a chemical reaction in which a cross-linking agent attaches itself to a DNA strand and prevents the normal parting of the strands during mitosis.

Cross-Linking Theory

• Over time, as these cross-linking agents accumulate, they form dense aggregates that impede intracellular transport; ultimately, the body’s organs and systems fail.

• An effect of cross-linking on collagen (an important connective tissue in the lungs, heart, blood vessels, and muscle) is the reduction in tissue elasticity associated with many age-related changes.

Mutation Accumulation Theory

• Suggests that aging occurs due to a declining force of natural selection with age.

• In other words, genetic mutations that affect children will eventually be eliminated because the victims will not have lived long enough to reproduce and pass this to future generations.

• On the other hand, genetic mutations that appear late in life will accumulate because the older individuals they affect will have already passed these mutations to their offspring.

Antagonistic Pleiotropy Theory

• suggests that accumulated mutant genes that have negative effects in late life may have had beneficial effects in early life.

• This is assumed to occur either because the effects of the mutant genes occur in opposite ways in late life as compared to their effects in early life, or because a particular gene can have multiple effects––some positive and some negative.

Disposable Soma Theory

Differs from other evolutionary theories by proposing that aging is related to the use of the body’s energy rather than to genetics.

Disposable Soma Theory

• It claims that the body must use energy for metabolism, reproduction, maintenance of functions, and repair, and with a finite supply of energy from food to perform these functions, some compromise occurs.

• Through evolution, organisms have learned to give priority to energy expenditure to reproductive functions over those functions that could maintain the body indefinitely; thus, decline and death ultimately occur.

Free Radicals and Lipofuscin Theories

Free radicals are highly reactive molecules containing an extra electrical charge that is generated from oxygen metabolism. They can result from normal metabolism, reactions with other free radicals, or oxidation of ozone, pesticides, and other pollutants.

Free Radicals and Lipofuscin Theories

• These molecules can damage proteins, enzymes, and DNA by replacing molecules that contain useful biological information with faulty molecules that create genetic disorders. It is believed that these free radicals are self-perpetuating; that is, they generate other free radicals. Physical decline of the body occurs as the damage from these molecules accumulates over time.

• However, the body has natural antioxidants that can counteract the effects of free radicals to an extent.

Beta-carotene, Vitamin C and E

antioxidants that can offer protection against free radicals

Autoimmune reactions

• Some theorists believe that the reduction in immunologic activities also leads to an increase in autoimmune response with age.

• One hypothesis regarding the role of autoimmune reactions in the aging process is that the cells undergo changes with age, and the body misidentifies these aged, irregular cells as foreign agents and develops antibodies to attack them.

Autoimmune reactions

• An alternate explanation for this reaction could be that cells are normal in old age, but a breakdown of the body’s immunochemical memory system causes it to misinterpret normal cells as foreign substances.

• Antibodies are formed to attack and rid the body of these “foreign” substances, and cells die.

Wear and Tear theories

• Attribute aging to the repeated use and injury of the body over time as it performs its highly specialized functions.

• Like any complicated machine, the body will function less efficiently with prolonged use and numerous insults.

Stress

This theory is limited in its universality because individuals react differently to life’s stress—one person may be overwhelmed by a moderately busy schedule, whereas another may become frustrated when faced with a slow, dull pace

Biogerontology

the study of the connection between aging and disease processes

Biogerontology

Although no conclusive evidence exists to link these pathogens with the body’s decline, interest in this theory has been stimulated by the fact that human beings and animals have enjoyed longer life expectancies with the control or elimination of certain pathogens through immunization and the use of antimicrobial drugs

Neuroendocrine and Neurochemical Theories

• Suggest that aging is the result of changes in the brain and endocrine

glands.

• Some theorists claim that specific anterior pituitary hormones promote aging.

• Others believe that an imbalance of chemicals in the brain impairs healthy cell division throughout the body.

solar elastosis

repeated exposure to ultraviolet light is known to cause _____, the “old age” type of skin wrinkling that results from the replacement of collagen by elastin.

ultraviolet light

also a factor in the development of skin cancer

Radiation Theories

• The relationship between radiation and age continues to be explored.

• Research using rats, mice, and dogs has shown that a decreased life span results from nonlethal doses of radiation.

• In human beings, repeated exposure to ultraviolet light is known to cause solar elastosis, the “old age” type of skin wrinkling that results from the replacement of collagen by elastin.

• Ultraviolet light is also a factor in the development of skin cancer.

• Radiation may induce cellular mutations that promote aging.

Nutrition Theories

• The importance of good nutrition throughout life is a theme hard to escape in our nutrition-conscious society.

• It is no mystery that diet impacts health and aging.

• Obesity is shown to increase the risk of many diseases and shorten life.

• The quality of diet is as important as the quantity.

• Deficiency of vitamins and other nutrients and excesses of nutrients such as cholesterol may cause various disease processes.

Nutrition Theories

• Recently, increased attention has been given to the influence of nutritional supplements on the aging process; Vitamin E, bee pollen, ginseng, gotu kola, peppermint, and kelp are among the nutrients believed to promote a healthy, long life.

• Although the complete relationship between diet and aging is not well understood, enough is known to suggest that a good diet may minimize or eliminate some of the ill effects of the aging process.

Environmental Theories

• Several environmental factors are known to threaten health and are thought to be associated with the aging process.

• The ingestion of mercury, lead, arsenic, radioactive isotopes, certain pesticides, and other substances can produce pathologic changes in human beings.

• Smoking and breathing tobacco smoke and other air pollutants also have adverse effects.

• Finally, crowded living conditions, high noise levels, and other factors are thought to influence how we age.

Person-Environment Fit Theory

• Functional competence is affected by multiple intrapersonal conditions such as ego strength, motor skills, biological health, cognitive capacity, and sensory-perceptual capacity as well as external conditions posed by the environment

• Degree of competency may change as one ages, affecting functional ability in relationship to environmental demands

• Persons’ ability to meet these demands is affected by their level of function and influences their ability to adapt to the environment

• Those functioning at lower levels can tolerate fewer environmental demands.

Psychosocial Theories of Aging

• Explore the mental processes, behavior, and feelings of persons throughout the life span, along with some of the mechanisms people use to meet the challenges they face in old age.

• Sociologic theories address the impact of society on older adults and vice versa.

Disengagement Theory

• Developed by Elaine Cumming and William Henry, this theory has been one of the earliest, most controversial, and most widely discussed theories of aging.

Disengagement Theory

• It views aging as a process in which society and the individual gradually withdraw, or disengage, from each other to the mutual satisfaction and benefit of both.

• The benefit to individuals is that they can reflect and be centered on themselves, having been freed from societal roles.

Disengagement Theory

• The value of disengagement to society is that some orderly means are established for the transfer of power from the old to the young, making it possible for society to continue functioning after its individual members die.

• The theory does not indicate whether society or the individual initiates the disengagement process.

Continuity Theory

• Referred to as the developmental theory, relates personality and predisposition toward certain actions in old age to similar factors during other phases of the life cycle.

• Personality and basic patterns of behavior are said to remain unchanged as the individual ages.

• Patterns developed over a lifetime will determine whether individuals remain engaged and active or become disengaged and inactive.

Continuity Theory

• The recognition that the unique features of each individual allow for multiple adaptations to aging and that the potential exists for a variety of reactions gives this theory validity and support.

• Aging is a complex process, and the continuity theory considers these complexities to a greater extent than most other theories.

• Although the full implications and impact of this promising theory are at the stage of research, it offers a reasonable perspective.

• Also, it encourages the young to consider that their current activities are laying a foundation for their own future old age.

Individualism Theory

• Individual personalities tend to view life primarily either through the self or through others

• As individuals age, elders engage in an “inner search” to critique their beliefs and accomplishments

• Successful aging means acceptance of the past and an ability to cope with functional decline and loss of significant others

• “Interiority” (introspection) promotes positive inner growth

Life-Course or Life Span Development Paradigm

• Life occurs in stages that are structured according to one’s roles, relationships, internal values, and goals

• Individuals may choose their goals but are limited by external constraints.

• Goal achievement is associated with life satisfaction

Life-Course or Life Span Development Paradigm

• Individuals must adapt to changing roles and relationships that occur throughout life, such as getting married, finishing school, completing military service, getting a job, and retiring

• Successful adaptation to life change may necessitate revising beliefs to be consistent with societal expectations.

Subculture Theory

• Older adults are a unique subculture within society that is formed as a defensive response to society’s negative attitudes and the loss of status that accompanies aging.

• Older adults prefer to interact among themselves

• Older adults have a social disadvantage regarding status and associated respect because of the functional decline that accompanies aging.

Age Stratification Theory

• Aging and society are interrelated and cause reciprocal changes in individuals, age group cohorts, and society

• Quality of life is integrated with functional capacity and dependency needs, and positive consequences are possible despite age-related limitations

Functional Consequences Theory

• Aging adults experience environmental and biopsychosocial consequences that impact their functioning

• Quality of life is integrated with functional capacity and dependency needs, and positive consequences are possible despite age-related limitations

Theory of Thriving

• Thriving is achieved when there is harmony between a person and his or her physical environment and personal relationships

• Failure to thrive is due to discord among the three elements (person, physical environment, and personal relationship).

• Nurses identify and modify factors that contribute to disharmony among these elements.

Developmental tasks

• Developmental tasks are the challenges that must be met and adjustments that must be made in response to life experiences that are part of an adult’s continued growth through the life span.

• Erik Erikson (1963) described eight stages through which human beings progress from infancy to old age and the challenges, or tasks, that confront individuals during each of these stages.

• The challenge of old age is to accept and find meaning in the life the person has lived; this gives the individual ego integrity that aids in adjusting and coping with the reality of aging and mortality.

• Feelings of anger, bitterness, depression, and inadequacy can result in inadequate ego integrity (e.g., despair).

Gerotranscendence

• A recent theory that suggests aging entails a transition from a rational, materialistic metaperspective to a cosmic and transcendent vision.

• As people age, they are less concerned with material possessions, meaningless relationships, and self-interests and instead desire a life of more significance and a greater connection with others.

Diet

A positive health state that can contribute to longevity is supported by reducing saturated fats in the diet, limiting daily fat consumption to less than 30% of caloric intake, avoiding obesity, decreasing the amount of animal foods eaten, substituting natural complex carbohydrates for refined sugars, and increasing the consumption of whole grains, vegetables, and fruits.

Activity

• Exercise is an important ingredient to good health.

• It increases strength and endurance, promotes cardiopulmonary function, and has other beneficial effects that can affect a healthy aging process.

Play and laughter

• Laughter causes a release of endorphins, stimulates the immune system, and reduces stress.

• Finding humor in daily routines and experiencing joy despite problems contributes to good health.

• It has been suggested since the time of Solomon that “a cheerful heart is good medicine, but a crushed spirit dries up the bones”

Faith

• A strong faith, church attendance, and prayer are directly related to lower rates of physical and mental illness.

• Religion and spirituality can have a positive effect on the length and quality of life.

Empowerment

• Losing control over one’s life can threaten self-confidence and diminish self-care independence.

• Maximum control and decisionmaking can have a positive effect on morbidity and mortality.

Stress Management

• It is the rare individual who is unaware of the negative consequences of stress.

• The unique stresses that may accompany aging, such as the onset of chronic conditions, retirement, deaths of significant others, and change in body appearance, can have significantly detrimental effects.

• Minimizing stress when possible and using effective stress management techniques are useful interventions.