Do we only have so much energy to expend in a lifetime?
restricting activities in insects may increase their life spans
some mammals live longer if hibernation is induced
the number of calories consumed is related to longevity
age of maturity in mammals is related to longevity
But — examination of many species does not support a direct relationship between metabolism and length of life
Cellular theories
replication senescence & telomeres
cross-linking
free radical damage
Programmed-cell-death theories
Physical changes is in Young Adulthood
Changes in physical appearance and declines in body functioning in the 20’s and 30’s tend to be gradual
organ reserve: the part of the total capacity of our body’s organs that we do not normally need to use
the most significant changes in organ reserve occur in the heart, lungs, and kidneys
“A 50-year-old man might fish all day with his 25-year-old son and take a long walk with him without becoming exhausted, but has little change of winning a footrace against him.” (Fiore, 2011, p. 210)
Sensory
gradual changes from approximate age 30 in vision and hearing
Cardiovascular: heart disease is leading cause of death in adult population
Respiratory
Maximum vital capacity declines by approximately 10 percent per decade after age 25
a common measure of overall aerobic fitness is Maximum oxygen uptake (VO2 max): the ability of the body to take in and transport oxygen to various body organs. At rest VO2 shows only minimal decrements with age; when measured during exercise (like a treadmill test), it shows a decline with age of about 1% a year, beginning between ages 35 and 40 (Goldberg, Dengel, & Hagberg, 1996)
Aging of the lungs can make it harder for older adults to meet the body’s need for oxygen while exercising
Immune System: declines after age 20, usually due to changes in thymus the compromise the immune response; is also weakened by psychological and physical stress
T cells are a type of white blood cell produced in the bone marrow and maturing in the thymus, attacks antigens (foreign substances in body) directly; shows most decline of immune system
B cells are a type of white blood cell produced in the bone marrow which secrete antibodies into the bloodstream to multiple, surround antigens, allowing the antigens to be destroyed by the body
Skin and hair: loss of elasticity; hair becomes thinner and may gray
Reproductive capacity
Women’s fertility decline with age, especially in late 30’s and in the 40’s
Men’s semen volume, sperm concentration and motility gradually decrease after age 35, contributing to reduced fertility rates in older men
Motor performance
Declines in heart and lung functioning during exertion, combined with graduate muscle loss, lead to changes in motor performance
In ordinary citizens, the impact of biological aging on motor skills is difficult to separate from decreases in motivation and practice
The upper biological limits of motor capacity is reached in first part of early adulthood, but biological aging accounts for only a small part of age-related decline until advanced old age
Middle Adulthood : physical development
Middle Adulthood: When does “middle” begin?
ages 40 to 65
midpoint, not end of life
continuations of adulthood changes
Physical Changes with Age
Vision: by the 40’s, visual “accommodation” becomes more difficult for nearby objects
by the 60’s, the lenses loses their capacity to adjust to objects at varying distances entirely, presbyopia (“old eyes”)
color vision declines, “night vision” declines
glaucoma–poor fluid drainage leading to destructive buildup of pressure in eye–becomes the leading cause of blindness
Hearing
about 14% of Americans between 45 and 64 suffer from hearing loss, often due to age-related changes called presbycusis (“old hearing”)
after age 50 high frequency loses become more apparent
gender, and possibly population differences
males have earlier, more rapid loss
Skin
the skin become less elastic and supple, “age spots” appear, blood vessels in the skin become more visible
sun exposure tends to exacerbate wrinkling and spotting
smoking
Voice
young adult voices tend to be full and resonate; older adult voices tend to be thinner or weaker
age related changes show lowering of pitch, increased breathlessness, and mumbling, slower & less precise pronunciation, decrease volume
may reflect changes in larynx, respiratory system, and muscles; may reflect poor health that are not part of normal aging
Muscle-Fat
both males and females tend to loss muscle mass and gain weight
basal metabolic rate slows, leading to a decreased caloric need (but not appetite)
weight bearing/resistance training exercise can help offset both excess weight and muscle loss
Skeleton
mineral content of bones declines, bones become more porous, and bone density declines
disk collapse in the spinal column lead to a decrease in height
great loss of bone density lead to the disorder of osteoporosis
Reproductive System
the climacteric, the mid-life transition in which fertility declines, brings an end to reproductive capacity in women and decreased fertility in men
menopause: estrogen production decreases over a decade the concludes with menopause, late 30’s to late 50’s–the end of menstruation and reproductive capacity
decreased genital size and sensitivity, become less easily stimulated, and the vagina lubricates more slowly during arousal
hot flashes and sexual problems are linked with menopause
common reports of less satisfying sleep, irritability, and mood problems are not clearly linked to menopause
psychological and physical effects
expectation and “meaning” dramatically affects the experience of menopause
marked cultural and subcultural differences
males experiences a decrease in quantities of semen and sperm produced after age 40, testosterone production reduces
erectile dysfunction–inability to attain/sustain an erection when desired–becomes more common in mid-life
drugs that increase blood flow to the penis and commonly prescribed for treatment
sildenafil (Viagra) was approved by the FDA in 1998 for treatment of erectile dysfunction in males
Behavior patterns/habits markedly influence health during mid-life
Type A behavior pattern: extreme competitiveness, impatience, angry outbursts
cardiac health and survival
the research literature: method variance, individual differences, and some “real” effect
hostility as the most dangerous element
Hardiness: control, commitment, and challenge that are associated with more adaptive coping with stress
regard most experiences as controllable
display a committed, involved approach to daily activities
view change as a challenge
Late Adulthood : physical development
Physical Development in late Adulthood
Life expectancy
“average life expectancy” is the number of years a person born in a particular year can expect to live
“average life expectancy” can also be defined as the age at which half of the people born in a particular year will have died
in 2008 the average life expectancy in the U.S. reach 78.1
declines in infant death rates have historically been a major contributor to increases in average life expectancy
advances in medical care also boosted average life expectancy over the 20th century
women tend to live 4 to 7 years longer than men, although this difference is decreased in industrialized nations
life expectancy varies with SES, ethnicity, and nationality BUT:
life expectancy in late adulthood shows decreased differences between males and females, and among ethnic and SES groups; possibly reflecting attrition of less healthy individuals
chronological age is an imperfect indicator of “functional age”: the actual competence and performance of the older adult
“Average healthy life expectancy” refers to the number of years a person born in a particular year can expect to live in full health, without disease or injury
Japan currently ranks first in average healthy life expectancy, in part due to low rates of obesity and heart disease, and favorable health care policies
in developing nations with widespread poverty, disease, and armed conflict; average life expectancy is about 50 years
Factors in a long life:
Heredity
Environment/Lifestyle
freedom from exposure to acquired diseases, toxins, pollutants
healthy diet, normal weight
exercise
low substance use
optimism
low stress
social support
community involvement
life long learning
Quality of life
“activities of daily living” (ADL’s) refer to basic self-care tasks needed to live independently (bathing, dressing, managing medications, keeping appointments, transportation). Some discussions consider ADL’s in two classes: basic self-care and “instrumental activities of daily living” (paying bills); but many discussions tend to consider ADL’s as a whole.
ADL’s may be much more situational they we commonly realize: why microwave ovens are the greatest invention of all time
the “Third Age” refers to a current view that old age is a time of potential growth rather than decline; sometimes characterized as the “good news” about aging
increased life expectancy
substantial potential for physical and cognitive fitness
evidence of cognitive and emotional reserves
high levels of emotional and personal well-being
effective strategies to master the gains and losses of later life
the “Fourth Age” refers to the “oldest old” who are at the limits of their functional capacity; sometimes referred to as the “bad news” about aging
sizeable losses in cognitive potential and ability to learn
increases in negative effects of chronic stress
high prevalence of dementia, frailty, multiple chronic conditions
problems with quality of life and dying with dignity
“Maximum lifespan”: the genetic/biological limit to the life of a person (excluding external risk factors)
for most of us it appears to be between 70 and 110, with 85 being a commonly cited average
approximately 120 years of life appears to be the upper limit on human life span, although this continues to be a point of debate among scientists
Physical Changes
Nervous system
the aging of the central nervous system affects a wide range of complex activities in the older individual
brain weight declines throughout adulthood, but the loss becomes greater beginning in the 60’s due to death of neurons and enlargement of ventricles within the brain
structural changes in the neuron that reduce the effectiveness of information transmission and processing by neurons
neurofibillary tangles — spiral-shaped masses formed when fibers that compose the axon become twisted together
neurotic plaques — structural changes produced when damaged and dying neurons collect around a core of protein
dendritic changes — reduction of dendritic branching
decline in neurotransmitters
Parkinson’s disease is caused by insufficient levels of dopamine, often treated with L-Dopa
growth of neural fibers in healthy older adults occur at similar rates as in middle-aged adults
elders who do well on complex cognitive activities (memory, problem solving) tend to show more widely distributed neural activity across the cerebral cortex–this is usually interpreted as their compensating for neuron loss by recruiting additional brain areas to support cognition
the autonomic (peripheral) nervous system, involved in many life support functions, also performs less well with age–putting the elderly at risk during heat waves and cold spells
Sensory systems
vision:
several changes lead to increasing problems with vision
lens become more yellow, causing poorer color discrimination in the green-blue-violet end of color spectrum
presbyopia: difficulty seeing close objects clearly
cataracts, opaque spots, develop on lenses of eyes
diseases and abnormal process may also damage vision
if fluid in the eye does not drain properly, glaucoma may result, glaucoma (untreated) can lead to blindness
diabetes can cause abnormal aging of arteries, with blindness being one of the serious side effects
hearing: presbycusis, reduced sensitivity to high frequency sounds
olfactory: sense of smell remains largely intact until after age 70, when declines are often seen
decreased vestibular sensitivity (and decreased muscle strength and response times) make older individuals increasing likely to fall
falls (and decreased bone density) lead to broken bones (often hips) lead to placement in rehabilitation facilities lead to (sometimes) loss of functional skills and ADL’s lead to (worse case) loss of home placement lead to (worse case) premature deterioration and (sometimes) death
balance enhancing activities (T’ai Chi) lead to fewer falls, & weight bearing exercise lead to preserved bone density; lead fewer falls, fewer breaks, fewer nursing home placements, etc.
Cardiovascular and respiratory systems
aging in the cardiovascular and respiratory systems (in the absence of disease) tends not to be markedly apparent until late adulthood
decreased blood flow limits the oxygen delivery to body tissues during high physical activity
Immune system
as the immune system ages, T cells, which attack antigens directly, become less effective
immune system malfunctions become more frequent, “autoimmune responses” or “autoimmune diseases” reflect the immune system attacking normal body tissue
decrease immune system efficiency increases the risk for a variety of diseases in the elderly
Sleep
older adults appear to require approximately the same amount of sleep as younger adults, around 7 hours a night
increased difficulty with falling asleep, staying asleep, and sleeping deeply is reported in the elderly and seen in sleep lab studies
these problems may reflect changes in the brain systems controlling sleep, and by higher levels of stress hormones in the bloodstream
restful sleep can be enhanced by “good sleep habits”: consistent bedtime and waking time, using the bedroom only for sleep and sex, regular exercise
prescription sedatives (sleep medications) can help relieve temporary insomnia but long-term use is often problematic