Senescence – progressive deterioration of body systems that can increase the risk of mortality as an individual gets older
Recent research has concentrated on learning about keeping people healthy and active for a longer period of time, rather than on extending their lives in a state of long-term disability. Recognizing the theories of aging offer varying degrees of universality, validity, and reliability. Nurses can use this information to better understand the factors that may positively and negatively influence health and well-being of persons of all ages.
There are multiple processes that can affect how we age. Aging is influenced by heredity, lifestyle, behavior, nutrition, and education level. Some changes are benign and superficial, such as graying of the hair and wrinkling of the skin, whereas others increase the risk of disease and disability, such as hardening of the arteries or arteriosclerosis. Many different theories have been formulated to describe the phenomenon of aging. These theories are physical, psychological, spiritual, and sociological in nature. Each hypothesis has been supported by research. However, no consensus has been reached that describes the entire aging process.
Aging has been defined as a change in an organism that begins at conception and progresses through a series of stages until death. The term senescence refers to the progressive deterioration of body systems. Age-related changes affect every body system. These changes are normal and occur as people age. The age at which specific changes become evident differs from person to person. The rate and progression of aging varies from one individual to the next and within the same person. For instance, a person may have gray hair at age 45 but relatively unwrinkled skin at age 80. Some of the changes are considered “plastic” or modifiable by lifestyle habits. Normal aging includes those universal changes that occur in all older people. Organ reserve declines at slightly different rates. It is important to distinguish chronological age (number of years from birth) from physiological age (degree of senescence experienced by each body system). Results of normal aging include the loss of organ reserve, or the ability of a given organ to react quickly and efficiently to physiological stress. Aging is characterized by a failure to maintain homeostasis under conditions of physiological stress, this failure is associated with decreased viability and increased vulnerability of the individual. Homeostasis - The regulation of bodily functions within precise limits in order to maintain ideal bodily function. Homeostenosis - The decline of the body's ability to maintain homeostasis as a result of decreased organ function in old age.
No one theory alone can suffice. Nursing’s role is to minimize age-associated disability in order to enhance safety and quality of living.
Biological Aging Theories – Broadly speaking, we can distinguish between two kinds of theories of aging. Pr ogrammed theories and error theories. Programmed theories – Aging follows a biological timetable and may represent a continuation of the cycle that regulates childhood growth and development. Some theories see aging as the result of an internal necessity, such as a built-in genetic program that proceeds inevitably in senescence and death. Error Theories – Aging is due to chance. The error theories emphasize the ravages of the environment to human systems that gradually cause things to go wrong. External events, such as accumulated random negative factors damage cells or body systems over time. The most popular error theories hypothesize that environmental assaults and the body’s constant need to manufacture energy and fuel metabolic activities cause toxic by-products to accumulate. These toxic by-products may eventually impair normal body function and cellular repair. Aging likely occurs as a result of a combination of intrinsic genetic factors upon which extrinsic environmental factors impact.
Programmed theories –Hypothesize that genes program age-related molecular and cellular events. The body’s genetic codes contain information for the regulation of cellular reproduction and death. Programmed Longevity – Cells divide until they are no longer able to; this triggers apoptosis or cell death. Aging is the result of sequential switching on and off of certain genes. In this theory it is proposed that there is an impairment in the ability of the cell to continue dividing. Aging is the result of the sequential switching on and off of certain genes, with senescence defined as the point in time when age-associated functional deficits are manifested. Persons who endorse this theory are interested in studying the human genome & genetic theories of aging. One of the major milestones in the contemporary biology of aging was the discovery that cells in laboratory culture have a fixed lifespan. In 1961, Leonard Hayflick and associates found that normal human cells in tissue culture go through a finite number of cell divisions and then stop. This maximum number of divisions is known as the Haflick limit. Hayflick found that cells replicate themselves around 100 times if they are taken from fetal tissue. But if taken from a 70-yr old, they reach their limit of “aging” after 20 or 30 divisions. Cells taken from older organisms divide proportionately fewer times than those taken from younger ones. Normal human cells that are frozen at a specific point in their process of replication and later thawed seem to “remember” the level of replication at which they were frozen. Furthermore, normal cells from a donor animal that are transplanted will not survive indefinitely in a new host. With aging there is loss of telomere strands in the cells which affect the number of times a cell can divide. Somatic cells have a fixed number of times they divide in life and have the ability to remember this programming under harsh conditions, “in-built cellular clock.” Neuroendocrine and Neurochemical Theories – Hormones control the pace of aging. Neuroendocrine and neurochemical theories suggest that aging is the result of changes in the brain and endocrine glands (Hypothalamus-Pituitary-Endocrine Gland Feedback System). These changes are accompanied by a decline in functional capacity in other endocrine organs, such as the adrenal and thyroid glands, ovaries, and testes. Proponents of this theory ascribe to the use of various natural and synthetic hormones, such as human growth hormone or estrogen replacement, to slow the aging process. Some theorists claim that specific anterior pituitary hormones promote aging (increased insulin growth factor). Others believe that an imbalance of chemicals in the brain impairs healthy cell division throughout the body. Aging occurs because of functional decrements in neurons and associated hormones. An important focus of this theory is the functional changes of the hypothalamic-pituitary system. Immunological Theory – Aging is due to faulty immunological function which is linked to general well being. This theory proposes declining functional capacity of the immune system as the basis for aging. The primary organs of the immune system, the thymus and bone marrow, are believed to be affected by the aging process. A programmed decline in immune system functions leads to an increased vulnerability to infectious disease, aging, and eventual death. Declines in immune system function can affect the outcomes of many illnesses such as postoperative infections, diabetes, urinary tract infections, and pneumonia. It also suggests that aging is not a passive wearing out of systems but an active self-destruction medicated by the immune system. This theory is based on observing an age-associated decline in T cell functioning, accompanied by a decrease in resistance and an increase in autoimmune diseases with aging. A breakdown in the body’s immunological memory system causes it to mistake normal cells as foreign and are attacked by the person’s own immune system. It is generally accepted that a healthy diet and lifestyle coupled with preventive health measures, such as a yearly flu shot or pneumonia shot and limiting exposure to pathogens, can support immune function.
Cross-Link Theory – Connective tissue in the body, such as the skin or the lens of the eye, loses elasticity with advancing age. We recognize the result as wrinkling of skin and cataracts. The explanation for this change lies in a substance known as collagen, a natural protein and connective tissue found in lungs, heart, blood vessels, and muscle. According to the cross-linkage theory of aging, the changes we see result from an accumulation of cross-linking compounds in the collagen, which gradually become stiff. Once the binding happens, the protein cannot perform normally The piling up of harmful molecules is thought to eventually impair cell function, by preventing normal parting of the DNA strands during mitosis. 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 is the reduction in tissue elasticity associated with many age-related changes. An accumulation of cross-linked proteins resulting from the binding of glucose (simple sugars) to protein (a process that occurs under the presence of oxygen) causes various problems. Once the binding occurs, the protein cannot perform normally and results in all sorts of problems such as cataracts or wrinkling and skin aging. Such changes in cell structure may explain the observable cosmetic changes associated with aging, such as wrinkles of the skin and stiffer arterial blood vessels. An accumulation of cross-linked proteins results from the binding of glucose to protein. The modern diet is often high in sugar and carbohydrates, and some nutritionists believe that low-carbohydrate diets can slow the development of cross-links. However, it is unlikely that such changes account for all of the detrimental physical events associated with aging. Wear & Tear Theory – 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. The human body, like all multicellular organisms, is constantly wearing out and being repaired. Cells wear out and cannot function with aging. Cells and organs have vital parts that wear out after years of use. Cellular function slows down with time and becomes less efficient at repairing body malfunctions that are caused by environmental assaults. Abusing or neglecting one organ or body system can stimulate premature aging and disease. The wear-and-tear theory is a good explanation for some aspects of aging – for example, the fact the joints in our hips, fingers, and knees tend to become damaged over the course of time. A case in point is the dz of osteoarthritis. Another is cataracts. Our hearts beat several billion times over a lifetime, so with advancing age, the elasticity of blood vessels gradually weakens, causing normal blood pressure to rise and athletic performance to decline.
Free-Radical Theory – Accumulated damage by oxygen radicals causes cells and eventually organs to lose function and organ reserve. The use of antioxidants is believed to slow this damage. Free radicals are highly reactive molecules containing an extra electrical charge that are generated from oxygen metabolism. They can result from normal metabolism, reactions with other free radicals, or oxidation of ozone, pesticides, and other pollutants. These molecules can damage proteins, enzymes, and DNA by replacing molecules that contain useful biological information with faulty molecules that create genetic disorder. Membranes, nucleic acids, and proteins are damaged by free radicals which causes cellular injury and aging. This process, also called oxidative stress, can ultimately disrupt cell membranes and alter DNA and protein synthesis. It is believed that these free radicals are self-perpetuating; that is, they generate other free radicals. Common diseases such as atherosclerosis, coronary artery disease, cataracts, and cancer are associated with oxidative stress. Free radicals are natural byproducts of many normal cellular processes. There are numerous natural protective mechanisms in place to prevent oxidative damage. The use of antioxidants and vitamins is believed to slow this damage. Recent research has focused on the roles of various antioxidants, including vitamins C and E, and beta-carotene that offer protection against free radicals. It is believed that these substances can slow down the oxidative process and ultimately the aging process. There has been considerable interest in the role of lipofuscin “age pigments,” a lipoprotein by-product of oxidation that can be seen only under a fluorescent microscope, in the aging process. As lipofuscin accumulates, it interferes with the diffusion and transport of essential metabolites and information-bearing molecules in the cells. The older a person is, the more lipofuscin in the body. Investigators have discovered the presence of lipofuscin in other species in amounts proportionate to the life span of the species. Somatic DNA Damage Theory – Genetic mutations occur and accumulate with increasing age, causing cells to deteriorate and malfunction. This is a more sophisticated versions of this original wear-and-tear theory. Advocates believe that genetic manipulation and alteration may slow the aging process. Radiation theories note that cells can be damaged by radiation and, as a result, mutate or experience genetic changes. Research on rats, mice, and dogs has shown that a decreased life span results from non-lethal doses of radiation. Errors in DNA and RNA synthesis occur with aging. Genetic mutations occur and accumulate with increasing age, causing cells and then organs to deteriorate and malfunction. Proponents believe that genetic manipulation and alteration may slow the aging process. 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 produce aging.
Lipofuscin is the name given to finely granular yellow-brown pigment granules composed of lipid-containing residues of lysosomal digestion. The pigment left over from the breakdown and digestion of damaged cells. Lipofuscin represents the presence of lysosomes that have accumulated a noticable amount of indigestible residue. Lipofuscin is sometimes called "wear-and-tear pigment", since the amount increases over time (i.e., with advancing age) in cells like hepatocytes and neurons which are both permanent (not routinely replenished) and metabolically active.
B. Cells undergo change and the body identifies them as foreign One hypothesis regarding the role of autoimmune reactions in the aging process is that the cells undergo change with age, and the body misidentifies these aged, irregular cells as foreign agents and develops a plan to attack them.
False. No single factor causes or prevents aging; therefore, it is unrealistic to think that one theory can explain the complexities of the aging process. The number, diversity, and complexity of factors that potentially influence the aging process show that no one biological theory can adequately explain the cause of this phenomenon.
Psychological or Sociological theories of aging - Changing roles, relationships, status and generational cohort impact the older adult’s ability to adapt.
Disengagement Theory – The disengagement theory has been one of the earliest, most controversial, and most widely discussed theories of aging. 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 disengagement theory states that “aging is an inevitable, mutual withdrawal or disengagement, resulting in decreased interaction between the aging person and others in the social system he belongs to.” This means that withdrawal from one’s society and community is natural and acceptable for the older adult and his or her society. Gradual withdrawal from society and relationships serves to maintain social equilibrium and promote internal reflection. Individuals can reflect and be centered on themselves; they are free from society roles. Society – some orderly means is established for the transfer of power from the older to the young, making it possible for society to continue functioning after its individual members die. The measures of disengagement are based on age, work, and decreased interest or investment in societal concerns. The theory is seen as universal and applicable to older people in all cultures, although there are expected variations in timing and style. Difficulties – no substantial base of research to support this theory. Many older people desire to remain engaged. Activity Theory – Argues that the more active elderly persons are, the greater their satisfaction with life. In order to maintain a positive sense of self, elderly person's must substitute new roles for those lost in old age. Remaining occupied and involved is necessary to a satisfying late-life. Opposite of disengagement theory. The activity theory asserts that an older person should continue a middle-aged lifestyle, denying the existence of old age as long as possible and that society should apply the same norms to old age as it does to middle age. Society should not advocate diminishing activity, interest, and involvement as its members grow old. Life satisfaction depends on maintaining an involvement with life by developing new interests, hobbies, roles, and relationships. The activity theory is based on the belief that remaining as active as possible in the pursuits of middle age is the ideal in later life. Because of improved general health and wealth, this is more possible now that when this theory was proposed 40 years ago. The activity theory may make sense when individuals live in a stable society, have access to positive influences and significant others, and have opportunities to participate meaningfully in the broader society if they continue to desire to do so. Activity is more desirable than inactivity because it facilitates physical, mental, and social well-being. Problem – Some aging persons are not able to maintain a middle-aged lifestyle. Many older adults lack the physical, emotional, social, or economic resources to maintain active roles in society. Also, income limitations (half income of middle-aged people) come into play.
Continuity Theory – The continuity theory of aging 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 unchanged as the individual ages. For instance, activists at 20 years of age will most likely be activists at 70 years of age. Whereas young recluses will probably not be active in the mainstream of society when they age. Key concept: Basic psychological patterns are consistent throughout the life span. Patterns developed over a lifetime will determine whether individuals remain engaged and active or become disengaged and inactive. The aging person substitutes new roles for lost ones, and continues to maintain typical ways of adapting to the environment. Personality influences, roles, and life satisfaction and remains consistent throughout life. Despite their age, older adults generally maintain the same traditions and beliefs. Past coping patterns recur as older adults adjust to physical, financial and social decline and contemplate death. Identifying with one’s age group, finding a residence compatible with limitations and learning new roles post retirement are major tasks. Major point – Individuals maintain their values, morals, and behaviors as they age. Successful methods used throughout life for adapting and adjusting to life events are repeated. Traits, habits, values, associations, and goals remain stable, regardless of life changes. 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 give this theory validity and support. Aging in a complex process, and the continuity theory considers these complexities to a greater extent than most other theories. It encourages the young to consider that their current activities are laying a foundation for their own future old age. In all three of the psychosocial theories of aging, the importance of opportunity, ethnicity, gender, and social status is largely ignored. None of the three theories can be clearly supported with data. In addition, they have little to do with personal meaning and motivation.
True. The continuity theory of aging relates personality and predisposition toward certain actions in old age to similar factors during other phases of the life cycle. For instance, activists at 20 years of age will most likely be activists at 70 years of age.
Developmental theory – Developmental tasks to be accomplished at each stage. Psychosocial Development - The task of the older adult includes ego integrity versus despair. Erik Erickson’s theory of psychosocial development is one of the best-known theories of personality in psychology. Erickson believed that personality develops in a series of stages. Erickson’s theory describes the impact of social experience across the whole lifespan. According to Erickson (195)), there are eight stages of life with developmental tasks to be accomplished at each stage. One of the main elements of Erickson’s psychosocial stage theory is the development of ego identity . Ego identity is the conscious sense of self that we develop through social interaction. According to Erickson, our ego identity is constantly changing due to new experience and information we acquire in our daily interactions with others. In addition to ego identity, Erickson also believed that a sense of competence also motivates behaviors and actions. Each stage in Erickson’s theory is concerned with becoming competent in an area of life. If the stage is handled well, the person will feel a sense of mastery. If the stage is managed poorly, the person will emerge with a sense of inadequacy. In each stage, Erickson believed people experience a conflict that serves as a turning point in development. In Erickson’s view, these conflicts are centered on either developing a psychological quality or failing to develop that quality. During these times, the potential for personal growth is high, but so is the potential for failure. The task of old age as balancing the search for integrity and wholeness, thus avoiding a sense of despair. He believed that successful accomplishment of this task, achieved primarily through life review activities, would result in wisdom. Erickson proposed that during this stage the older adult will become preoccupied with acceptance of eventual death without becoming morbid or obsessed with these thoughts. If major failures or disappointments have occurred in the older person’s life, this final stage may be difficult to accomplish because the older person may be despairing rather than accepting of death. Older persons who have not achieved ego integrity may look back on their lives with dissatisfaction and feel unhappy, depressed, or angry over what they have done or failed to do. Psychological counseling can help to resolve some of these issues.
1. Theories of AgingNURS 4100 Care of the Older AdultSpring 2013Joy A. Shepard, PhD(c), MSN, RN, CNE,BC 1
2. Objectives Discuss the change in focus regarding learning about factors influencing aging List the major biological theories of aging Describe the major psychosocial theories of aging Identify factors that promote a healthy aging process Describe implications of theories of aging 2
3. Definitions Compression of morbidity – Healthy old age, followed by rapid decline & death (“Health Span”) Homeostasis - The regulation of bodily functions within precise limits in order to maintain ideal bodily function Homeostenosis - The decline of the bodys ability to maintain homeostasis as a result of decreased organ function in old age Life expectancy – Expected years of life from birth Maximum life span – Maximum possible length of life Senescence (old age) – Point in time when age- associated functional deficits are manifested 3
4. Focus of Research on Aging Better understanding “Successful aging” of aging process: Avoiding disease & Healthier lifestyles disability Postponement of Maintaining mental & negative consequences physical function Healthy & active Continuing Understanding factors engagement with life that influence health and well-being 4
5. The Aging Process The aging process is multifactorial, includes: Benign changes, such as graying hair Nonbenign changes, such as senescence Individualized aging progression Modifiable changes related to lifestyle Normal or universal aging processes 5
6. The Aging Process Senescence: Normal aging includes progressive Loss of organ reserves deterioration of body resulting in decreased systems response to Characterized by failure physiological stress to maintain homeostasis Variations among under conditions of individuals physiological stress Chronologic & (homeostenosis) biological aging, which Decreased viability, are not synonymous increased vulnerability Organ system changes of individual 6
7. Aging: Many Interrelating Factors, Causes No single factor, theory Heredity, nutrition, health status, life experiences, environment, activity, & stress Aging is highly individualized 7
8. Theories of aging includebiological, psychological,sociological, and spiritual aging 8
9. Biological Theories of Aging “FATE” - Internal Program theories of aging (Genetic) Genetically programmed events cause cellular damage that accelerates aging of the organism “CHANCE” - External Error Theories (Environmental) Random events cause cellular damage that accumulates as organism ages 9
10. Programmed Theories Programmed Longevity Genetic clock (Hayflick limit) Human genome Neuroendocrine & Neurochemical Theories Immunological/ Autoimmune Theory Changes in immune function with aging Diminishing of thymus, impaired immunologic function 10
11. Error Theories of Aging Cross-Linking Theory Loss of flexibility, diminished functional motility Wear & Tear Theory Effects of stress Stress causes structural & chemical changes resulting in irreversible tissue damage 11
12. Error Theories of Aging Free Radical Theory Oxygen radicals, antioxidants Lipofuscin Nutrition theory Somatic Mutation (DNA Damage) Theory Radiation Theories Decreased function & efficiency of cells & organs Solar elastosis – “old age” type of skin wrinkling 12
13. Solar Elastosis: ChronicExposure to Solar Radiation(UV) 13
14. Lipofuscin 14
15. Question Which of the following statements best describes the autoimmune theory of aging? A. Genetic programs determine life expectancy B. Cells undergo change and the body identifies them as foreign C. Organs decline as a result of cellular mutations D. Failure of the production of a growth substance causes aging cells to die 15
16. Question Is the following statement true or false? The genetic theories of aging best describe how and why a person ages 16
17. Psychosocial Theories of Aging Disengagement theory Activity theory Continuity theory Developmental tasks Erik Erikson 17
18. Sociological Theories of Aging Social & Psychological Models: Dynamic interplay betweens gains & losses Disengagement Theory As individuals age, they inevitably withdraw from society Society withdraws from them Separation mutually agreed upon Activity Theory Continue middle-age lifestyle; deny existence of old age Life satisfaction: involvement in new interests, hobbies, roles, and relationships Volunteering: one way retirees stay connected to community 18
20. Question Is the following statement true or false? The continuity theory of aging states that personality and basic patterns of behavior are said to remain unchanged as the individual ages. 20
21. Developmental: Erickson Final Stage - Integrity vs. Despair Old Age (after age 65) - Reflecting back on life Successful in accomplishments – Feel sense of integrity Few regrets, satisfaction Attain wisdom, even when confronting death “Only when we are so old, only, we are aware of the beauty of life.” Alice Herz Sommer, age 106 Unsuccessful - Feel life was wasted, many regrets Bitterness, despair, depression, anger 21
22. Developmental Challenges Associated with Aging Certain developmental challenges bring opportunities for older people to experience feelings of success, loss Social relationships, roles Retirement The strengths of each Coping with loss Death of a loved one individual (including past Living arrangements coping skills) must be Loss of independence identified & utilized when Financial challenges planning care Fixed income 22
23. Opportunities for Older People to Experience Feelings of Success Gaining insight or wisdom, self- understanding, self-acceptance Deepening gratitude & appreciation Gaining new knowledge & experiences Developing better social skills, coping ability Enhancing creativity & confidence Developing new skills, hobbies, & interests 23
24. Opportunities for Older People to Experience Feelings of Success Civic & community positions of responsibility Seeing children transform into responsible, successful adults Becoming a grandparent Renewing & deepening one’s relationship with one’s spouse, significant others, or friends Accepting & adjusting to physical changes associated with aging Pursuing spiritual interests 24
25. More Challenging Developmental Tasks Death of a spouse Major declines in health or physical ability Physiologic changes may result in losses, causing impairments in communication, vision & learning, mobility, cognition, or psychosocial skills Loss of social role, prestige, occupation, income Loss of independent living Accepting a fixed income 25
27. Erikson Question Which of the following best reflects Erikson’s description of the old age task of reconciling ego integrity with despair? A. 75-year-old woman who is insecure and has developed a general attitude of mistrust concerning the world. B. 77-year-old man who fears death as he struggles to find purpose in his life, reflecting upon his experiences and failures. C. 78-year-old woman who has unresolved feelings of inadequacy and inferiority, which shows in her relationships with friends and acquaintances. D. 80-year-old man who has not been successful in finding deep intimacy and satisfying relationships and now feels isolated. 27
28. Implications of Theories of Aging No single theory can adequately explain aging process Knowledge of all theories: guide nursing interventions to promote health and longevity Sensitivity to the impact of attitudes toward aging on patients themselves 28
29. Interesting Quotation… Do You Agree? “Aging is a self-fulfilling prophecy. If we dread growing old, thinking of it as a time of forgetfulness and physical deterioration, then it so likely to be just that. On the other hand, if we expect it to be full of energy and anticipate that our lives will be rich with new adventures and insight, then that is the likely reality. We prescribe who we are. We prescribe what we are to become” (Bortz, 1990, p. 55). Bortz, W. (1990). Use it or lose it. Runner’s World, 25, 55-58. 29