Controversy 2Why Do Our Bodies Grow OldWhy Do Our Bodie.docx

Controversy 2
Why Do Our Bodies Grow Old?
Why Do Our Bodies Grow Old?
Moody, Aging 9e. SAGE Publishing, 2018.
The maximum lifespan for the human species appears to be
around 120 years
We have no valid records of people living much beyond 120
years
Over recent years, life expectancy (e.g., average number of
years lived) has risen; but lifespan (e.g., maximum possible
length of life) hasn’t changed at all
How long are you going to live? (6:55)
127-year-old women is the world’s oldest living person (0:52)
2
Why Do Our Bodies Grow Old? (cont.)
Compression of Morbidity theory: suggests we should aim for a
healthy old age, followed by a rapid decline and death, which
would likely:
Enhance the quality of life
Extend life expectancy and “health span”
Reduce health care costs and caregiver burden
3
The Process of Biological Aging
Senescence (Normal Biological Aging): an underlying time-

dependent biological process that, although not itself a disease,
involves functional loss and susceptibility to disease and death.
Gompertz Law—death rates for contemporary humans double
every 8 years (ex., a 38-year-old would be twice as likely to die
as a 30-year-old)
Additionally, at any given age, men are twice as likely to die as
women
The Science of Aging (2:05)
4
The Process of Biological Aging (cont.)
Comparative Anatomy—the study of the structure of different
species
Helps us understand differences in aging and lifespan across
species
The rate of aging can be correlated with the amount of time it
takes the death rate of a species to double
e.g., the doubling time for humans is 8 years, but it is 10 days
for a fruit fly and 3 months for a mouse
5
The Process of Biological Aging (cont.)
Rate-of-Living Concept—the concept that metabolism and life
expectancy are closely related
Smaller organisms, which have faster metabolisms, also have
shorter life expectancies
Human beings have an average lifespan and maximum life
expectancy about twice as great as those of any other primate
6

Biological Theories of Aging
No single theory of aging explains all the complex processes
that occur in cells and body systems
But ongoing research is finding new insights into why we grow
old
7
Biological Theories of Aging (cont.)
Two basic kinds of theory of aging:
Chance—the result of external events
Fate—the result of an internal necessity
The question remains whether or not it’s possible to intervene
to correct damage to the aging body or modify the genetic
program
8
Wear-and-Tear theory—sees aging as the result of chance
A good explanation for some aspects of aging, such as the fact
that our joints and bones become damaged over time as an
outcome of living
9
Somatic Mutation theory—notes that cells can be damaged by
radiation, and as a result, mutate or experience genetic changes
A more modern and sophisticated version of the wear-and-tear
theory, but little science evidence to support it at this point

10
Error Accumulation theory (aka error catastrophe theory)—
posits that decremental changes of senescence are the result of
chance or random changes that downgrade the genetic code
Over time, small errors in genetic coding occur and eventually
make the later copies unreadable (e.g., like using a photocopy to
make another copy)
11
Accumulative Waste theory—suggests that the accumulation of
waste products eventually interferes with cell metabolism and
leads to death
According to scientific research, although waste products do
accumulate, there is little evidence of harm to the organism
12
Autoimmune theory—the system may eventually become
defective and no longer distinguish the body’s own tissues from
foreign tissues
The body may then begin to attack itself, as suggested by the
increase with age in autoimmune diseases, such as rheumatoid
arthritis, that result from inflammatory processes
13

Aging-Clock theory—claims that aging is programmed into our
bodies like a clock ticking away from conception
14
Cross-Linkage Theory—claims that the bodily changes that we
see as we age result from the accumulation of cross-linking
compounds in the collagen, which gradually becomes stiff
Collagen—a natural protein found in the skin, bones, and
tendons
15
Free Radicals—damage created by free radicals (molecules that
appear as a byproduct of oxygen metabolism in cells) eventually
gives rise to the biological changes associated with aging
The body produces anti-oxidants—substances that protect
against free radicals that prevent damage to cells
Free Radicals (2:05)
16
Cellular Theory—argues that aging ultimately results from the
progressive weakening of capacity for cell division, perhaps
through exhaustion of the genetic material
Hayflick limit—the finite number of cell divisions that normal
human cells in tissue culture go through
Named after discoverer Leonard Hayflick (1961)

17
Is Aging Inevitable?
The biological aging process may not be the result of a rigid
genetic program:
It may simply be the complex and indirect result of multiple
traits in the organism tied to normal development
18
Is Aging Inevitable? (cont.)
But aging is not a disease
Rather, it’s a normal process of change, part of which may make
us more vulnerable to disease
And the process is life-long, beginning the moment we are born
19
Environmental and Genetic Approaches
There is only one environmental intervention that has
scientifically been shown to be connected to longevity in
mammals: restricting food intake
When caloric intake is reduced—by up to 40% fewer calories
than normal—aging-related deterioration slows down, and
aging-related diseases are diminished
This is possibly because caloric reduction slows metabolism—
the rate at which food is transformed into energy
For any individual, length of life will be the result of both
genetic and environmental factors
20

Compression or Prolongation of Morbidity?
Various environmental and genetic alterations have been shown
to increase lifespan among simple organisms
But human beings are more complex, and there is still no
conclusive evidence from research on humans
21
Compression or Prolongation of Morbidity? (cont.)
According to the book, the compression of morbidity theory
stands out as an important reminder of how critical biological
research will be for the future of an aging society
22
Reading 5: Why Do We Live as Long as We Do?
Discuss Hayflick's basic premise regarding the increase in
longevity of the human species. What are the key aspects—and
implications—of his premise?
23
Reading 6: Vitality and Aging
Fries and Crapo, writing in the 1980s, provided a “new
syllogism” about human aging. What are the key components of
their model of biophysical aging? Is there any indication that
what they propose in their model has been borne out in the past
two decades as more people reach later life and research on
biological aging has expanded?
24

Reading 7: The Compression of Morbidity Hypothesis
What are the key components of the “compression of morbidity
hypothesis”? While author Mor agrees that there have been
improvements in the rate of late life morbidity, he questions
whether this trend will continue into the future. What are some
of the reasons for his concern?
25
Reading 8: Health Trends in the Older Adult Population
Parker and Thorslund assert that “a concept of general
morbidity is not sufficient when discussing health trends and
the need for care services in the elderly population.”
What do they propose as an alternative?
26
Reading 9: We Will Be Able to Live to 1,000
If Aubrey de Grey’s proposal for curing aging were to come to
pass, what would aging and later life look like? What would
society look like?
27
Reading 10: Don’t Fall for the Cult of Immortality
Olshansky provides a counter argument to de Grey’s agenda to
“cure aging.”
What are the key ideas in Olshansky’s argument? Taken
together, which side of the debate do you find to be more
compelling? More realistic?
28

Basic Concepts 1
A Life Course Perspective on Aging
Concepts for Thinking About the Meaning of Age
2
Age identification: refers to both how many years have passed
since we were born as well as an individual's experiences of the
aging process
Age differentiation: certain roles and behaviors are considered
appropriate based on chronological age
2
Concepts for Thinking About the Meaning of Age (cont.)
3
Age grading: refers to the way people are assigned different
roles in society based on their age
Age stratification: theory that a person’s position in the age
structure affects behavior or attitudes
The Stages of Life
4
Humans have always seemed to recognize a progression through
the life course, no matter how long it is, from young age to old
age.
However, views of how humans age and the meaning and

expectations attached to certain ages have changed over time
and vary by culture.
4
The Stages of Life (cont.)
5
Example: In the Western world, during different historical eras
there were different views of the human progression through the
life course.
The Stages of Life (cont.)
6
Since the middle of the 20th century, because of increases in
longevity, distinctions are made between certain stages of life,
based on chronological age groups and the assumption that
members of the group have things in common:
“Young-Old”: ages 65–74
“Old-Old”: ages 75–84
“Oldest-Old”: ages 85 and over
The Many Faces of Aging (7:23)
Moved on 3.6.17 by VW-G
6
Traditional Theories of Aging
7

Modernization Theory: claims that the status of older adults
declines as societies become more modern
Old age was valued in agricultural society where the elders
controlled the land
Traditional Theories of Aging (cont.)
8
Disengagement Theory: considers old age to be a time when
both the older person and society engage in mutual separation
(e.g., retirement from work)
One of the earliest attempts to explain old age in modern
society
Doesn’t always refer to the outward behavior of people—can
mean an inner attitude toward life
9
Activity Theory: argues that the more active people are, the
more likely they are to be satisfied with life
Opposite view of Disengagement Theory
May be difficult for “old-old” people because of physical
changes with aging
10
Continuity Theory: claims that people who grow older are
inclined to maintain as much as they can of the same habits,
personality, and style of life they developed in earlier years
Similar to Activity Theory in asserting that decreases in social
interaction are better explained by poor health or disability,

rather than some functional need of society to “disengage” older
people from their previous roles
The Life Course and Aging
11
Aging is increasingly viewed from a “Life Course” perspective
Span of a lifetime = total number of years we live
Course of life = the meaningful pattern seen in the passing of
time
Earlier experiences are thought to influence how aging and later
life are experienced
The Life Course and Aging (cont.)
12
An individual's characteristics—class, race/ethnicity, gender,
sexual identity, etc.—are seen as important as well
Longitudinal design is the research methodology used to follow
how development unfolds in individuals over time and is the
primary approach used to study the life course.
Influences on the Life Course
13
All theories have limits: none fully explains the many ways
individuals experience old age
Many also reflect social values in uncritical ways (e.g., setting
up either activity or disengagement as the ideal goal in old age)
Influences on the Life Course (cont.)

14
Most pervasive view of adulthood assumes continuous
deterioration and decline
Gives priority to biological factors and is the basis for age-
based prejudice called Ageism
AGEISM (2:22)
Ageism Towards Older People (6:31)
Seniors in Pop Media (3:10)
I recommend removing the AGEISM (2:22) video since it is
somewhat specific to Canada. I have included a different
Ageism video that is more definitions and information to what
ageism is.
Ageism towards older people added 3.6.17 by VW-G
14
15
Social class and life history affect one’s path through the life
course
Also, other factors such as earlier life events, social/cultural
historical events, unpredictable non-normative life events, etc.
have an influence
16
Social institutions and policies have structured the life course in
modern times, and define transitions throughout life

This may provide order and predictability, or it may foster
dependency on the system
Examples: “learned helplessness” and “excess disability”
The Big Idea in 4 Minutes - Coming of Age In Aging America
(4:48)
Aging in the 21st Century
17
Today, we no longer have a shared map for the course of life
Time and the Life Course—there are many expectations about
how much time should be spent in certain stages of life
e.g., time spent devoted to education, childbearing, etc.
Aging in the 21st Century (cont.)
18
The Moral Economy of the Life Course—embodies expectations
of what is fair or right
The old moral economy that distributed work and leisure
according to chronological age is losing its power
Aging in the 21st Century (5:47)
Discussion Question
19
Are there any new aging expectations or patterns that seem to
be emerging in the 21st century?

The Biology of Aging
20
The new science of longevity—on a biological level, aging
results from changes in cells, tissues, etc.; so we understand the
process by comparing young cells to old ones
Cross-sectional methodology—looks at the physical function of
people at different chronological ages, but at a single point in
time (e.g., looking at a 1-, 10-, 20-, and 30-year-old on April
25, 2016)
The Biology of Aging (cont.)
21
Biomarkers—biological indicators that can identify features of
the basic process of aging (ex., blood pressure, eyesight and
hearing abilities, etc.)
Reserve capacity—the body’s ability to recover from assaults
and withstand high demands during physical exertion
22
For each species, there is a different:
Lifespan: the maximum number of years a member of a species
can survive
And
Life expectancy: the average number of years an individual can
be expected to live after birth taking into account environmental
factors

23
Lifespan and Life expectancy are related but not the same thing.
A newer concept is “health span”: the number of years of health
and well-being a person experiences.
Mechanisms of Physical Aging
24
Wear and Tear: the balance between the body’s exposure to
damage and its ability to repair itself shifts, and it becomes
harder for the body to heal itself
Free Radicals: ionized oxygen molecules are the waste products
that result from continuous cell metabolism and may contribute
to physical aging
Mechanisms of Physical Aging (cont.)
25
The Immune System: the immune system’s job is to defend the
body against invaders such as viruses, bacteria, and parasites;
with normal aging, the body’s ability to fight invaders declines
Aging and Psychological Functioning
26
A long-term research project spearheaded by Rowe and Kahn
introduced the concept “successful aging” and explored the
important connections among the following:
Self-concept and social relationships
Social roles
Cognitive functioning

Physical health
Discussion Question
27
The “successful aging” concept is not without its critics. What
might be some of the underlying assumptions of this approach?

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