Transcript Physiological & Clinical Changes of Aging

Physiological and Clinical
Changes of Aging
Pio L. Oliverio, MD
Fellow, Geriatrics
SVCMC, Jamaica, NY
OBJECTIVES
1.
2.
To describe basic concepts of
physiologic changes with aging
To describe the effect of aging
on body processes/ systems
DEFINITION of TERMS

Aging – the process of growing
old, specially by failure of
replacement cells in sufficient
number to maintain full functional
capacity
(Stedman’s Med Dictionary 2000)
DEFINITION of TERMS

Aging – the gradual deterioration of a
mature organism resulting from timedependent, irreversible changes in structure
that are intrinsic to the particular species,
and that eventually lead to decreased ability
to cope with the stresses of the environment
thereby increasing the probability of death
(Stedman’s Med Dictionary 2000)
DEFINITION of TERMS

Aging – is a process that converts
healthy adults into frail ones with
diminished reserves in most
physiologic systems and exponentially
increasing vulnerability to most
diseases and to death
(W. Hazzard, Principles of Geriatric Medicine & Gerontology 2003)
DEFINITION of TERMS
Gerontology – the scientific study
of the process and problems of
aging.
 Geriatrics – the branch of medicine
concerned with the medical
problems and care of the aged
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DEFINITIONS of
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Life Span
A lifetime
The average or maximum length of time an
organism or object can be expected to survive
or last
The maximum number of years that a person
has been known to live, currently around 115
years
Frequently confused with life expectancy
DEFINITION of
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Life Expectancy
length of time that a person on the average is
expected to live
average number of years of life remaining to a
person at a particular age and is based on a
given set of age-specific death rates
Also Average Life Span or Mean Life Span
Can change over life cycle
Based on statistical probabilities
Average Life Expectancy
(In years)
61 – developing countries
74 – developed countries
VARIATIONS in life expectancy
WORLD WIDE
 Causes: differences in public health
medicine and nutrition from country
to country
USA + other developed countries
 Variation in ethnicity and gender
FACTORS
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Poverty
Air pollution
Occupation
Diet
Access to
health care
affecting life expectancy
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Genetic
disorder
Exercise
Smoking
Excessive
drug and
alcohol use
Fundamental Considerations
1.
2.
3.
4.
Aging is developmental
Old age is a gift of 20th century
technology and scientific advancement
The effects of normal aging vs.
pathologic aging must be differentiated
There is no universally accepted theory
of aging
Theories of Aging
Oxidative stress (free radical) Theory
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Tissue damage is caused by free radicals
(super oxide or hydroxyl radicals) through
lipid peroxidation
Specific form of wear and tear theory
Accumulation of aging pigments (lipofuscin)
in lysosomes
Theories of Aging
Rate of Living Theory
(Metabolic Rate Theory)
• The higher the basal metabolic
rate (the rate, at which the body
at rest, uses energy), the
shorter the life span
Theories of Aging
Error Catastrophe Theory
• DNA errors promote senescence,
programmed cell death (apoptosis)
• Aging results from gene interference
with the ability of the cells to reproduce
Theories of Aging
Error Catastrophe Theory
Redundant DNA Theory
• Biologic age changes are a result of
errors accumulating in functioning genes
• Lifespan may be a degree of repeated
genetic sequences
• Fails to explain other possible aging
factors
Theories of Aging
Hayflick Limit Theory
• Functional changes within cells are
responsible for aging
• Cumulative effect of improper
functioning of cells and eventual loss of
cells in organs and tissues
Cardiovascular System
Morphology:
1. Elongation and tortuosity, stiffening of
arteries including aorta
2. Increase intimal thickening of arteries
3. Increased fibrosis of media of arteries
4. Sclerosis of heart valves
Cardiovascular System
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Cardiac Hypertrophy with aging
Inotropic and chronotropic responses to
catecholamines sympathetic nervous
system are impaired
Both systolic and diastolic blood
pressures increase with age
Blood pressure regulation: older patients
are at high risk for orthostatic hypotension
Cardiovascular System
 Decreased
• Cardiac output
• Heart rate response to
stress
• Compliance of
peripheral blood vessels
Respiratory System
 Decreased
• Lung elasticity
• Activity of cilia
• Cough reflex
• Respiratory drive
Respiratory System
 Lower…
•
Respiratory muscle
strength & endurance
• Diffusing capacity
(oxygen uptake)
• PO2, O2 saturation due to
V/Q mismatch (but no
change in PcO2 )
Respiratory System
 Lower
• Maximal expiratory flows:
• VC
FEV1, FEV1/FVC
 Increased
• FRC and RV
 Stable
• TLC
Renal System
 Decreased
• Number of nephrons
• Kidney weight and
volume
• Lean body mass
• Maximum urine
osmolality
Renal System
 Decreased
• Renal blood flow
• Creatinine clearance
• Renin response to
volume depletion or
salt restriction
Renal System
Impaired:
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Hydroxylation of Vitamin D
Metabolism of PTH, calcitonin and
glucagon
Unchanged:
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Erythropoietin production
Musculoskeletal System
Most common disability cause in > 65 years old
Decrease in:
• Muscle mass
• strength of grip/ contractile force
• stability of neuromuscular innervation
• Bone substance (osteoporosis)
• Height and Weight
Gastrointestinal System
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Decreased:
• Hydrochloric acid production
• Taste buds
• Intestinal motility
• Swallowing coordination
• Vitamin K-Dependent factor synthesis
Gastrointestinal System
Increased:
• Lithogenic index of bile composition
(cholesterol gallstones)
Functional Changes (Large Intestine):
• Slowed transit
• Altered coordination of contraction
• Increased opioid receptors (drug induced
constipation)
Endocrine System
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Decreased:
• Free testosterone
• Triiodothyronine
• Cortisol production
• Hypothalamic-pituitary-adrenal axis
sensitivity to glucocorticoid feedback
Endocrine System
 Increased:
• Insulin
• Norepinephrine
• Parathoromone
• Vasopressin
Immune System
 Impaired
thermal regulation
• Afebrile infection common
 Total
lymphocyte counts do not
change with age
 TNF-alpha increased but not
interleukin-1
Immune System
Decreased:
 Humoral antibody-mediated response
 Antibody response to vaccines
 Production of thymic hormones
 Mass of thymus
• Production of lymphocytes
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T-cell activity
Vision
Retina becomes thinner
 Changes in lens and iris =
presbyopia
 Cataract formation:
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• Lens yellows and accumulation of
insoluble protein in center…
Vision
Decreased:
• Lacrimal gland
function
• Tear production
• Goblet cell
function
• Acuity
• Accomodation
• Color sensitivity
• Depth
perception
• Pupil size
• Aqueous humor
production
Hearing
External auditory canal atrophies
 Cerumen becomes drier
Hearing Loss caused by:
 Loss of hair cells in the organ of Corti
 Loss of cochlear neurons
 Stiffening of the basilar membrane
 Calcification of auditory mechanism
 Degeneration of spiral ligament
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Thermoregulation
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Increased susceptibility to
hypo/hyperthermia
Impaired vasoconstrictor response to
cooling
Impaired ability to conserve heat
Impaired skin vasodilatation response
Decreased sweat production
Sexual Function
Slower arousal phase
 Increased ability to stay at plateau
levels of arousal
 Estrogen loss reduces acidity of
vaginal secretions, causes atrophic
vaginitis and hot flashes
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Sexual Function
In men, a longer refractory period
 In older men, erectile dysfunction
impotence. There is no such thing
as male menopause
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THANK YOU!
for your attention
and your time