Chapter 3 Physical Changes Notes

3.1 Why Do We Age? Biological Theories of Aging

• Theories aim to explain normative age-related changes, seeking to identify universal patterns in aging processes across individuals.

• Over 300 theories exist, highlighting the complexity of aging; none fully explain it, indicating that aging is likely multifactorial.

• Scientists hope to unlock genetic codes for answers, exploring the role of genes in determining lifespan and healthspan.

Metabolic Theories

• Commonsense theory: Organisms have limited energy, suggesting a finite amount of energy available for life processes.

• Metabolism rate is related to lifespan: Higher metabolic rate may correlate with shorter lifespan, and vice versa.

• Hormone production changes are associated with aging: Declining hormone levels can influence various aging-related processes.

• Caloric restriction may increase longevity but has downsides: Reducing calorie intake without malnutrition might extend lifespan but could impair quality of life.

• Circadian rhythms interact with caloric restriction: The body's internal clock influences the effectiveness of caloric restriction.

• Extreme caloric restrictions may lower quality of life: Severe dietary limitations can lead to health issues and reduced well-being.

Cellular Theories

• Aging is attributed to causes at the cellular level: Changes and damage to cells accumulate over time, contributing to aging.

• Hayflick Limit: Cells have a fixed number of divisions before dying.

  • Number of divisions decreases with donor organism's age, indicating that cells from older organisms have fewer replication cycles remaining.

  • Human fetal tissue cells: 40-60 divisions.

  • Adult human cells: ~20 divisions.

• Telomeres: Tips of chromosomes that shorten with each cell replication, impacting cell division and response to stress.

  • Telomerase enzyme is needed to fully reproduce telomeres during DNA replication but is not present in somatic cells. It maintains or lengthens telomeres, counteracting shortening.

  • Shortened telomeres lead to unstable chromosomes and replication cessation (See Figure 3.1). Critical shortening triggers cellular senescence or apoptosis.

  • Cancer cells may proliferate due to telomerase not regulating cell growth; effective cancer treatments may target telomerase production. Cancer cells often reactivate telomerase, allowing them to bypass normal cellular limits on division.

  • Telomeres can be lengthened: Interventions may increase telomere length and potentially reverse cellular aging signs.

  • Chronic stress accelerates telomere shortening, indicating that psychological stress can affect cellular aging.

  • Moderate exercise may maintain or slow the rate of telomere shortening: Regular physical activity might protect telomeres from shortening.

• Cross-Linking: Proteins interact randomly, creating stiffening molecules.

  • Collagen proteins are affected and make up ~1/3 of body protein (like reinforcing rods in concrete). Collagen cross-linking reduces tissue elasticity.

  • Increased cross-links stiffen muscles and arteries, reducing flexibility and increasing cardiovascular risk.

  • Cross-linking's impact on metabolic processes is not well-established. Further research is needed to clarify how cross-linking affects metabolism.

• Free Radicals: Unstable molecules produced during normal metabolism, causing cell damage. Oxidative stress from free radicals damages DNA, proteins, and lipids.

  • May cause heart cell damage by altering oxygen levels resulting in cardiovascular issues.

  • Potentially involved in Alzheimer's disease development. Free radicals may contribute to neurodegeneration in Alzheimer's.

  • Antioxidants (vitamins A, C, E, coenzyme Q) prevent free radical development by neutralizing them.

  • Antioxidant ingestion may postpone age-related diseases, but no direct evidence of lifespan increase. Supplementation has mixed results in extending lifespan.

Genetic Programming Theories

• Aging is programmed in genetic code. Genes influence longevity and susceptibility to age-related diseases.

• Programmed cell death is influenced by:

  • Physiological processes.

  • Innate ability of cells to self-destruct (apoptosis).

  • Dying cells triggering processes in other cells.

  • External environmental factors: Environmental conditions can affect genetically programmed aging processes.

• Genetic aspects are associated with diseases, including Alzheimer's. Specific genes increase the risk of developing Alzheimer's.

Implications of Developmental Forces

• Biological theories describe biological forces that influence aging.

• Unified theory of aging must account for biological, psychological, sociocultural, and life-cycle changes. Comprehensive understanding requires integrating multiple perspectives.

• Diagnosis and treatment must include multiple perspectives to

3.2 Psychological Changes

• Psychological changes are diverse and influenced by various individual factors, so they are not universal.

• Cognition and mental health are two key aspects of psychological changes during aging.

3.2.1 Cognition

• Cognitive abilities change as people age, but the degree and nature of these changes vary significantly among individuals.

  • Some abilities remain stable, some improve, and others decline.

• Five general areas of competence:

  • Attention: Older adults may experience declines in sustained attention and inhibitory control.

  • Sustained Attention: Maintaining focus on a task for an extended period.

  • Inhibitory Control: Ignoring distracting information.

  • Memory: Age-related changes in memory are common; however, the type of memory affected can vary.

  • Difficulties with episodic memory (recalling specific events) increase, while semantic memory (general knowledge) remains stable.

  • Executive Function: Cognitive processes that regulate, control, and manage other cognitive functions.

  • Declines can affect reasoning, problem-solving, and planning abilities.

  • Language: Language abilities are generally well-maintained in older adults.

  • Some individuals may experience difficulties with word retrieval, but overall comprehension and vocabulary remain intact.

  • Intelligence: Fluid intelligence (problem-solving and abstract reasoning) tends to decline with age, while crystallized intelligence (accumulated knowledge) remains stable or may even increase.

  • Fluid Intelligence: Problem-solving and abstract reasoning.

  • Crystallized Intelligence: Accumulated knowledge.

3.2.2 Mental Health

• Mental health is critical for well-being at all ages, including older adulthood.

  • Prevalence rates for depression and anxiety in older adults range from 1% to 5% for depression and 1% to 10% for anxiety disorders.

  • Late-life mental disorders are often associated with chronic illnesses, reduced physical functioning, and social isolation.

• Common mental health issues in older adults:

  • Depression: Characterized by persistent sadness, loss of interest, and feelings of hopelessness.

  • Anxiety Disorders: Excessive worry, fear, and nervousness that interfere with daily life.

  • Dementia: Cognitive decline that impairs memory, thinking, and behavior.

  • Can affect mood and behavior, leading to symptoms of depression, anxiety, or agitation.

  • Suicide: Older adults have a higher suicide rate than other age groups.

  • Factors contributing to suicide in older adults include social isolation, loss of loved ones, chronic illness, and financial difficulties.

3.3 Socio-Cultural Influences

• Sociocultural factors significantly affect how individuals experience and navigate aging.

  • Cultural norms, societal expectations, and socioeconomic conditions play crucial roles.

3.3.1 Ageism

• Ageism involves prejudice and discrimination against individuals based on their age.

  • It can manifest in various forms, including negative stereotypes, discriminatory practices, and social exclusion.

• Impacts of ageism on older adults:

  • Health: Ageism can negatively affect physical and mental health outcomes.

  • Well-being: Impacts overall quality of life and life satisfaction.

  • Social Interactions: May lead to social isolation and reduced opportunities for social engagement.

3.3.2 Cultural Norms

• Cultural norms shape attitudes toward aging.

  • Perceptions of aging vary widely across cultures.

  • Collectivistic cultures tend to value older adults for their wisdom and experience.

  • Individualistic cultures may prioritize youth and independence, leading to potential marginalization of older adults.

3.3.3 Socioeconomic Factors

• Socioeconomic factors influence the resources and opportunities available to older adults.

  • Income, education, and access to healthcare significantly impact the aging experience.

  • Older adults with higher socioeconomic status tend to have better health outcomes and greater access to social support.

  • Older adults from marginalized communities may face additional challenges due to systemic inequalities and discrimination.

• Strategies to promote successful aging in marginalized communities:

  • Income Security: Ensuring access to adequate financial resources.

  • Healthcare Access: Reducing disparities in healthcare access and quality.

  • Social Support: Strengthening social networks and community resources.

3.4 Life-Cycle Factors

• Life-cycle factors, including earlier experiences, shape aging.

  • Each stage of life influences subsequent development and well-being.

3.4.1 Earlier Experiences

• Childhood and adulthood experiences affect later life outcomes.

  • Early life adversity, such as poverty or trauma, can have long-lasting effects on physical and mental health.

  • Positive experiences, such as supportive relationships, can promote resilience and healthy aging.

3.4.2 Social Roles and Transitions

• Transitions through different social roles (e.g., marriage, parenthood, retirement) impact aging.

  • Marriage: Provides social support and companionship, which can enhance well-being in older age.

  • Parenthood: Parenting experiences and relationships with adult children can influence emotional well-being.

  • Retirement: A significant life transition involving changes in work roles, social networks, and daily routines.

3.4.3 Coping Strategies

• Coping strategies used throughout life affect adaptation to age-related changes.

  • Problem-focused coping: Directly addressing stressors.

  • Emotion-focused coping: Managing emotional responses to stressors.

  • Adaptive coping strategies promote resilience and psychological well-being in older age.

3.5 The Person-Environment Perspective

• The person-environment perspective emphasizes the interaction between individuals and their surroundings.

  • It examines how physical, social, and environmental factors affect older adults’ well-being and functioning.

3.5.1 Environmental Factors

• Physical and social environments impact aging.

  • Physical Environment: Features of the environment (e.g., housing, neighborhood, access to transportation) can either support or hinder older adults’ independence and quality of life.

  • Social Environment: Includes social networks, community resources, and opportunities for social engagement.

3.5.2 Person-Environment Fit

• Person-environment fit refers to the match between the individual’s needs, abilities, and preferences and the characteristics of their environment.

  • When the environment meets an individual’s needs, it promotes well-being and optimal functioning.

  • Conversely, when there is a mismatch between the individual and the environment, it can lead to stress, frustration, and reduced quality of life.

3.5.3 Environmental Press

• Environmental press refers to the demands that the environment places on the individual.

  • High environmental press can overwhelm older adults who have limited physical or cognitive resources.

  • Low environmental press may lead to boredom and under-stimulation.

• Balancing environmental press and individual competence is essential for promoting successful aging.

3.6 Successful Aging

• Successful aging involves maintaining physical, cognitive, and social well-being despite age-related changes.

  • It is a multidimensional concept that encompasses various factors, including health, social engagement, and personal growth.

3.6.1 Three Components of Successful Aging

• Three components of successful aging (according to Rowe & Kahn, 1997):

  • Avoiding Disease and Disability: Minimizing the risk of chronic diseases and maintaining physical functioning.

  • Maintaining High Cognitive and Physical Function: Preserving cognitive abilities and physical health.

  • Engagement with Life: Staying socially active and engaged in meaningful activities.

3.6.2 Critiques of Successful Aging

• Critiques of successful aging concept:

  • Overemphasis on Individual Responsibility: Ignores structural factors that influence aging.

  • Lack of Inclusivity: May exclude individuals with chronic illnesses or disabilities.

  • Cultural Bias: Reflects Western values of independence and productivity.

3.6.3 Alternative Perspectives

• Alternative perspectives on aging