Aging: Theory and Age Related Changes

biological age

the condition of the individuals’ organ and body systems

• People who have been active and exercised are likely to have a “younger” biological age than those individuals who are sedentary

psychological age

the individuals’ ability to adapt, solve problems, and cope with life events

Ex. A 90 year old may be physically weak but interested in life events and quite mentally active

social age

Habits, beliefs, and attitudes

Ex. Young adults may have had to take on the role of supporting a family while still in

their teens, so they may have the behavior of the cautious, conservative behavior of a

much older person vs. the behavior of a typical teen

Takeaway: look at the person first!

senescence 

the process of biological aging

predetermined

life expectancy is _ with cells programmed to divide a certain number of times

aging

• Functional changes in cells cause the _ of cells

• Aging is based on an internal genetic “ticking clock” and follows a preset biological timetable

• DNA cannot duplicate itself indefinitely and as we age the replication of cells slow

hayflick limit 

named after the Dr. Leonard Hayflick, name of this slowing of cell replication

programmed longevity

aging is a result of a sequential switching on/off of certain genes. Also states that senescence is when these age-related deficits are manifested

endocrine theory

proposes that biological clocks act through hormones to control the pace of aging

immunological theory 

proposes that the immune system is programmed to decline over time, which leads to an increased vulnerability to infectious disease, and thus aging and death

random error theories

or stochastic theories

Consist of several specific theories based on the effects of random events occurring over time and include free radical generation, gradual wear and tear, mutation over time, and differences in metabolic rate

wear and tear theory

cells wear out from repeated use, slowly killing themselves and then the body

somatic mutation theory 

random chromosomal changes occur due to miscoding, translation errors, chemical reactions, irradiation, and replication errors, causing changes in the genetic sequence and slowly reducing cell viability

cross-linking theory

an accumulation of cross-linked proteins damages cells and tissues, slowing down bodily processes and resulting in aging

free radicals theory 

superoxide and other free radicals cause damage to the macromolecular components of cells, and the damage causes cells and eventually organs to stop functioning

successful aging models

• The approach used most often by rehabilitation professionals

• Model of health and well-being instead of illness and degeneration

• Emphasizes the importance of adaptation and emotional well-being in successful aging

• Because physical function is decreasing as we get older, prevention of disease and keeping physically healthy is an important factor of successful aging

• Research shows that older adults put more emphasis on the psychosocial factors as keys to successful aging and less emphasis on longevity and absence of disease

components of successful aging

• Avoiding Disease and Disability

• High Cognitive and Physical Functioning

• Participation in Leisure Activities

• Engagement with Life

occupational balance 

• Individuals find their lifestyle to be harmonious and cohesive when they have occupational balance

• When obligatory and discretionary activities are not balanced, there is less feeling of satisfaction due to less occupational balance

middle adulthood

• Adults who are established in their adult roles

• 40-65 years old

• Due to postponement of childbearing and marriage in early adulthood, and advances in life expectancy in late adulthood, the period of family caregiving responsibilities has extended

central developmental tasks

learning to express love through more than sexual contacts, be proud of accomplishments, to maintain standard of living, and to adjust to the physiological changes of aging

sandwich generation 

• Refers to middle-aged adults caught between providing support or caregiving to both older and younger cohorts in the population

• When younger generations bring their own children along, there may be four generations living in one house

Baby Boomers (1944-1964)

• “gloomiest generation”

• Research shows _ rate their overall quality of life lower than younger people and are concerned their income won’t keep up with inflation (despite the fact they have the highest income of any age group)

• Perhaps related to extended caregiving strain or economic recession

gradual neurogenesis

balanced by gradual shrinkage of the hippocampus, some parts of the cortex, and the cerebellum

brain and nervous system (middle adulthood) 

• Significant individual differences in shrinkage rates

  • Healthy diet, exercise, and genetics all potentially protect against brain tissue loss

• Brain changes begin in Middle Adulthood and extend throughout the the rest of the life span

• Usually are not enough to affect the overall function of the individual

cognitive functions (middle adulthood)

• The evidence is clear that cognitive performance remains stable for most people during middle adulthood

• Individuals usually don’t have noticeable changes in performance until late middle adulthood or late adulthood

• People fear loss of cognitive abilities the most when it comes to aging

• Biological risk factors are associated with midlife cognitive decline

  • Protective risk factors are education, work, and exercise

• One study found that middle adulthood is a period of peak performance with inductive reasoning, spatial orientation, vocabulary, and verbal memory

vision (middle adulthood)

Normal age-related changes begin around age 50

Changes with vision occurring with age:

• Decreased lens transparency

• Decrease in the amount of light contacting the eye

• Decrease in the number of macular neurons have  approx. half from the ages of 20-80 years old

absolute threshold

the smallest detectable level of a stimulus

• with vision, refers to the smallest about of light required to see an object

• As they get older, people may need more light to read or difficulty seeing at night

difference threshold

the smallest change in stimulation that people can detect

• improvements in lighting and choosing materials with greater visual contrast, the difference thresholds are easily accommodated for

visual accomodation

the process during which the eyes adjust their focus, whether to the near or far objects, to gain clarity

• This process becomes less effective with aging

presbyopia

the result of the diminished ability to accommodate; an age-related decline in the eyes’ ability to focus on near objects

Presbycusis

Age-related hearing loss; slow and usually not noticeable until after the age of 60

Sensorineural Hearing Loss

hearing loss that results from prolonged exposure to very loud noises

• Due to poor cochlear hair cell function

• Affects individuals’ sensitivity to sound, speech comprehension, and maintenance of equilibrium

sensory functions: hearing (middle adulthood)

• The absolute threshold for sound also increases with age

• Increase in difficulty hearing high-frequency sounds begin to develop as early as 30

physical functions (middle adulthood) 

• Advances in medicine and preventative health care have allowed people to live longer

• Average life expectancy for a baby born in the US is 74.8 years old for males and 80.2 years for females

• Longer life expectancy will lead to greater percentage of people experiencing age-related physiological changes

• Strong evidence suggests that physical activity and healthy lifestyles in middle age can lead to less physical decline later in life

bone remodeling

the dynamic balance between the absorption of bone tissue (osteoclastic functions)

and simultaneous deposition of new bone (osteoblastic functions)

• These functions are in equilibrium until about after 35 years old, then bone loss will begin to exceed bone formation

osteoporosis

occurs when the body fails to form enough new bone when too much old bone is reabsorbed by the body, or both

• Multifactorial metabolic bone disease with environmental and genetic causes

• Most common type of bone disease in this age group

• Leading causes: drop in estrogen in women and a drop in testosterone in men

• Women over 50 and men over 70 have a higher risk of developing this

arthritis 

• a disease condition involving inflammation of one or more joints

• Cartilage: connective tissue that covers joint surfaces absorbs shock and provides a surface for sliding and rolling between joints

• With aging, the above process is disrupted and results in dehydration, poor nutrition, and increased degradation of these weight-bearing surfaces

osteoarthritis

when cartilage between bones is worn thin and the bones rub against each other, resulting in stiffness, pain, and loss of joint ROM

• Age-related form of arthritis and most commonly affects joints in the hands, knees, hips, and spine

• Most common form of arthritis, associated with various risk factors such as obesity, previous joint injury, and age

risk factors for osteoarthritis

• Genetics

• Age

• Weight

• Previous Injury

• Occupation Hazards

• Some High-Level Sports

• Illness or Infection

muscloskeletal changes 

• Lean body mass and bone density begin to decrease

• Changes are influenced by activity level, genetics, and other lifestyle factors

• Strength training in particular can help delay and even avoid some of the natural deterioration seen in aging muscles

• Muscle force production begins to slightly decline in 40-65 years

• Decrease in flexibility

• Gradual until age ~49, then more significantly drops

sarcopenia

a decline in the total number of skeletal muscle fibers according to size and type (tends

to affect Type II-fast twitch the most)

aerobic capacity

• the maximal amount of physiological work that individuals can do as measured by oxygen consumption

• Greatly affected by age- and disease-related processes

• Measure of aerobic capacity = Metabolic Equivalent Unit (MET)

• Common measure of cardiovascular fitness

• Cardiovascular fitness can protect against the changes in BMI, sarcopenia, and osteoporosis in middle-age

hypertension 

• High blood pressure

• Leading risk factor for heart disease and stroke

• Can also lead to kidney disease and vision problems

• Adults with hypertension are more likely to have other chronic conditions including cognitive impairments later

• Risk Factors: African American heritage, obesity, frequent stress or anxiety, high alcohol consumption, family hx of HTN, diabetes, and smoking

cardiovascular disease

• Diseases of the heart and blood vessels

• Atherosclerosis: a condition that develops when plaque builds up in the walls of the arteries

• Narrows the arteries, making it harder for blood to flow

• Coronary Artery Disease (CAD): narrowing of the arteries

• Heart Attack (Myocardial infarction or MI)

• Abnormal Heart Rhythms: arrhythmias

• Congestive Heart Failure (CHF)

• Heart Valve Disease

• Vascular Disease- blood vessel disease

• One of the leading causes ofmorbidity and mortality in both middle and late adulthood

diabetes metilius

• A group of metabolic diseases where people have high blood sugar, either because the body does not produce enough insulin or because cells do not respond to the insulin being produced

• Type 2 diabetes (AKA adult-onset diabetes) is the most common form

• Results from insulin resistance

• Obesity and lifestyle factors significantly impact the development of this condition

• The body’s fat, liver, and muscle cells do not respond correctly to insulin, resulting in insulin resistance

• Blood sugar does not get into the cells to be stored for energy and high levels of sugar builds up in the blood (hyperglycemia)

cancer

• Uncontrolled growth of abnormal cells in the body (also called malignant cells)

• Can develop in almost any organ or tissue

• The likelihood that an individual can develop cancer increases with age

• One of the more challenging aspects is managing the disruption that occurs with everyday life

• Uncertainty around the disease can be really overwhelming for patients and their families

• Physical, psychological, and social implications of the diagnosis and treatment