Transcript Aging and Organ Systems - UNIMORE

Aging of the Organ Systems
Nancy V. Karp, Ed.D., P.T.
[email protected]
Change


Life is a process of continual change.
Age-related changes occur at many levels.
– Biological level
– Physiological level
– Psychological level
– Functional level

During adulthood, there is a slow decline in
function. As you age, homeostasis is maintained
at a level of decreased function.
Change

This presentation will focus on some of the changes that
occur in different organ systems as they age.
 Physical therapists must recognize these changes to:
– determine how to objectively measure the extent of the changes;
–
–
i.e., changes in muscle function.
modify physical therapy interventions to accommodate these
changes.
prevent unnecessary therapy complications resulting from functional
and structural changes to organs or systems.
Remember
“Average” or “Normal” does not imply
“Optimal” or “Healthy.”
“Average” does not apply to an individual.
Elders are a heterogeneous population.
On the average, they are a
“normal” height.
Age-related Changes In The
Cardiovascular System
Normal Cardiovascular Changes
Related to Aging



The changes I am about to present are
considered a NORMAL part of the aging
process.
These changes occur with age. They are not
associated with pathological conditions.
There is some controversy over the
contribution of aging vs. disease to some of
the changes that are presented.
Cellular Changes

Alterations of DNA, RNA, mitochondria and
other sub-cellular changes are seen with
aging.

This changes result in decreased cellular
activities resulting in:
– altered homeostasis
– altered protein synthesis
– altered degradation rates
Cellular Changes

The myoctye cells of the heart increase in size.
– This may account for the myocardial wall thickening
that is seen with aging.
– Some myocytes are replaced by fibrous tissue.

Amyloid deposits in the myocardium increase with age.
– 50% in persons 70+
– They are not present in ALL older persons.
– Often seen in other organs (Alzheimer’s dx)
Cellular Changes

There is a decrease in pacemaker cells at the sinoatrial
node.
– Occurs around the age of 60
– 10% decrease by age 75

A smaller decrease of cells is seen in the
atrioventricular node and the Bundle of His
Cellular Changes
Thickening and calcification of heart and
vessels occur.
– Cells become irregular in size and shape.
– By age 50, the aorta has thickened 40%.
– There is a thickening of aortic, pulmonary and
–
heart valves.
98% of aortas have some calcification by age 40
Heart Changes



Modest increase in left ventricular wall
thickness (myocytes). This is exaggerated
with hypertension.
Slight enlargement of the left ventricular
cavity
Myocardial stiffness during contractions. The
walls of the heart are less compliant
Ventricular Hypertrophy

The enlarged left ventricular wall has a
decreased ability to expand during diastole.
– Results in reduced and delayed filling
– The left ventricle contracts less and ejects less

blood.
There is an increase in left atrium size,
secondary to the decline in left ventricle
compliance.
This increases the work load on the atria.
Vessel Changes
Arterial
Age causes the walls of the arteries to thicken
and to become less flexible.
– Thickening results from cellular accumulation and
–
–
matrix deposition.
Increase in arterial diameter size accompanies
thickening and loss of elasticity.
Dilated vessels have a limited ability to dilate in
response to increase blood volume.
Vessel Changes
Arterial
The decrease in the elasticity of vessels results in:
– Increased arterial pressure
– Increased peripheral resistance
– Residual increase in vessel diameter
– Vessel wall rigidity
– Fragmentation of the internal elastic membrane
– Increases in collagen and changes in cross-linking
collagen which cause the vessel to be less elastic
Vessel Changes
Venous

The ability of the vessel to contract is decreased.
– Dilation and tortuosity of veins results in decreased venous
–

return.
The Frank-Starling relationship of the heart changes stroke
volume which is dependent on venous return.
Little research has been done on the aging veins
–
The electrical excitability and responsiveness to the
autonomic nervous system is less rapid and
pronounced.
Heart Rate

Supine resting heart rate (HR) does not change very
much with age.

Sitting position HR decreases with age.

Respiratory sinus arrhythmia decreases with age.
– 104 beats/minute at age 20
– 92 beats/minute at age 45-50
Heart Rate

The maximum exercise heart rate decreases
with age.
– 200 beats/min at age 20
– 150 beats/min at age 80

The decline in maximal heart rate with age is
independent of fitness level.
What is the maximum exercise
heart rate ?

Not all patients will have a graded exercise test
(GXT) to determine the maximum heart rate.
Most elderly patients do not have a GXT.
 “Rule of Thumb” to calculate estimated maximum
exercise heart rate:
– 220 minus the patient’s age
– patients with pathological conditions
200 minus the patient's age with a standard deviation of 10
Stroke Volume

No significant changes in resting stroke volume is
seen with age.

Age may effects stoke volume during exercise.
– Reduction in the rate of filling ventricles secondary to
diminished diastolic compliance (preload)
Filling in early diastole is less and is greater in later diastole
– Stroke Volume may be decreased during exercise
Cardiac Output
Cardiac Output = Stroke Volume X Heart Rate
(ml/min)
(ml/cycles)
(cycles/min)
Declines slightly with age as a function of other
age-related changes.
Cardiac Output
Stroke Volume
Strength of
Contraction
End-diastolic
Volume
Heart Rate
SA Node
Autonomic
Regulation
Blood Pressure
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
Changes in blood pressure (BP) caused by aging is
difficult to separate from changes in blood pressure
caused by cardiovascular disease.
There are very few elderly people with no cardiovascular
disease in which to study normal BP changes.
Blood pressure = Cardiac Output X Total Peripheral Resistance
Increases in BP with age is a result of changes in total
peripheral resistance and aortic compliance.
Blood Pressure

Systolic BP tends to increase with age throughout
life
– 5-8 mm Hg per decade after 40-50 years of age
– an index of arterial stiffness

Diastolic BP tends to increase until the age of 60,
then it stabilizes or slowly declines
Generally increases 1 mm Hg per decade
Summary Slide
Aging Effects on the Heart
1. Structural changes at the cellular level
2. Decrease in SA cells and autonomic
nerve function
3. Thickening and calcification of heart and
vessels
4. Myocardial stiffness
5. Decreased elasticity of vessels
6. Decreased venous return
7. Decreased maximum heart rate
8. Changes in cardiac output,stroke
volume and blood pressure
All the changes that have been
discussed so far relate to a
person at rest.
What Happens When You
Exercise ?
“Perhaps the single, most salient and agerelated difference is the diminishing ability of
the body to respond to physical and emotion
stress…”
Carole Lewis
Jennifer Bottomley
Age-Related Changes During
Exercise

Aging changes (impairments) are seen when the
system is stressed.

The cardiovascular system must support the exercise
by increasing O2 in working muscles.
The Maximum Oxygen Consumption (VO2 max) is
considered an indicator of cardiovascular fitness.
Maximum Oxygen
Consumption (VO2 max)
VO2max is the maximum
amount of oxygen that
your heart can pump and
your muscles can use in a
given period of time.
VO2max is the product of
maximum cardiac output
and maximum systemic
arteriovenous O2
difference.
Just for Fun- Check this out!
http://www.brianmac.demon.co.uk/vo2max.htm#score
Changes During Exercise

The response of heart rate to exercise is
decreased in an elderly heart when compared
to a younger heart. This is due to:
– reduction of vagal tone
– impaired neural activation/release

Stroke volume during exercise can be10-20%
less in elderly patients compared to younger
adults.
Changes during Exercise
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Cardiac output increases with increasing loads.
The reasons for increased cardiac output vary when
comparing young adults and the elderly.
– In young adults, stroke volume is increased by an
–
increased HR and decreased end-systolic volume due to
beta-adrenergic stimulation
In the elderly, stoke volume is increased by an increase in
end-diastolic volume (shift in the Frank-Starling
relationship).
Maximum Aerobic Power
(Aerobic Capacity)

Aerobic Capacity declines 1% per year in adults
when measured by VO2max. The measurement of
VO2max is dependent on age-related changes in:
– Maximum heart rate
– Cardiac output
– Decreased muscle mass
– Decreased skeletal muscle quality
 Older persons in good physical condition can match
or exceed the aerobic capacity of unconditioned
younger persons.
Age-related Changes In
Muscles
Aging Muscles

Age-related reductions in muscle mass are a
cause of:
– decreased muscle strength
– disability
– gait and balance problems

Between 30-75 years old, the number and
size of muscle fiber progressively deceasessarcopenia
Sarcopenia
“Healthy” Young Adult
“Normal” 75 Year Old
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30% of weight is muscle

15% of weight is muscle

20% of weight is
adipose tissue

40% of weight is
adipose tissue

10% of weight is bone

8% of weight is bone
Aging Muscles
 There is a decrease in total muscle cross-sectional
area.
– 40% decrease by 80 years
– increase in fat and connective tissue
– decrease in protein synthesis

The faster-contracting type II fibers decrease at a
greater rate than type I fibers.
– Loss of maximum isometric contraction force
– replaced with fat and fibrous tissue
– angulated fibers and atrophy are seen in elderly
– Over time, Type I fibers greatly outnumber Type II fibers.
Aging Muscles
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Blood flow to the muscles is decreased.
– Results in decreased endurance capacity.
– Capillary density decreases which makes less O2
available during muscle work.

Decreased Enzyme Activity
– Aerobic enzymes decrease resulting in
–
mitochondrial decay.
Increased mitochondrial DNA deletions and
mitochondrial mutations appear.
Neuromuscular Changes

There is a decrease in the number of motor units
– Motor neuron innervates more muscle fibers
– Seen after 60 years
– More come in distal muscle groups

The number and diameter of motor axons decreases.
– After 60, there is a reduction in spinal cord axons
– Surviving segmental neurons branch and display collateral
growth.
Changes is Muscle
Performance

Muscle strength decreases
– Beginning at 30, strength decreases 8% per decade.
– The rate of decrease is similar for both males and females,
– Muscle strength loss is greater in leg muscles than in arm
muscles.

There is a significant decease in strength by age 70.
– 20 -40% decrease in maximal isometric strength
– Strength is related to sustainable walking speed
Changes is Muscle
Performance
Power and Endurance
– Power = rapid force generation
Decreased power is associated with decreasing walking speed
and a decreased ability to climb stairs.
– Endurance- stresses the cardiovascular system
– Contributes to functional loss
– Reduced blood supply
– Altered muscle contractibility and metabolism
Changes is Muscle
Performance
Velocity
– The maximal speed of muscle contraction
–
–
decreases with age
This is seen in “slowly moving” elders.
Also seen as the inability to quickly regain balance
resulting in a fall.
.
So far, two major aging systems
have a significant impact on an elderly
person’s ability to move.
What happens when you add exercise as
your PT intervention to these aging
systems
Fact of Fiction ?
Muscle bulk will never be normal.
Fatigue is a part of aging.
Exercise improves function.
How do you Assess the Need
for Exercise ?
How do you measure strength?
How do you measure fatigue?
How do you measure endurance?
How do you measure muscle atrophy?
How do you measure the success of the
exercise intervention?
How do you know the type and intensity for
exercise?
Age and Exercise
Skeletal and cardiac muscle change
according to the intensity, duration, and
frequency of physical activity.
– Changes occur at the cellular, tissue, and
–
performance level
Exercise is one of the few interventions that can
restore or improve physiologic capacity once it has
been lost.
Age and Exercise
Regular exercise benefits
– Preserve or improve skeletal muscle strength and aerobic
–
–
–
–
–
–
–
–
capacity
Improve bone density
Increases insulin sensitivity and glucose tolerance
Reduces resting BP
Normalizes blood lipid levels
Reduces fat
Contributes of mobility and independence
Decreases falls
Reverses decline
Exercise Specificity


The type of exercise chosen elicits different changes
in metabolic and physiological systems.
– Resistance training increases strength.
– Aerobic exercise increases endurance.
– Isometric exercise increases blood pressure????
Strength and endurance training adaptations may
occur independently or concurrently.
Exercise Prescription
Many factors must be considered
– Medical conditions
– Medications
– Response to exercise
– Postural or physical limitations
– Cardiopulmony functioning
– Mental functioning
– Functional level
– Type of monitoring or supervision
– Motivation
– Goals
Strength Training

Increases muscle fiber size and enzyme
activity
– Hypertrophy
– Increase in muscle volume without increase in
mitochondria
Elderly persons with disuse atrophy can increase
muscle size with strength training.

Increases bone mineral density
Strength Training
 The intensity of the training, not the overall fitness
level, determines the amount of gain in muscle
strength and size.
 Strengthening exercises need to be performed at
least 2 days/week for large muscle groups.

Use one-repetition maximum as guide
– 60-89 % of max is considered high intensity for the elderly
– Under very close supervision high intensity exercise yields
good result in the frail elderly.
Aerobic Exercise/
Endurance Training
Regularly performed aerobic exercise, not the
undying fitness level, determines the amount of
adaptive response.
Adaptive responses include:
– increased stroke volume and ventricular end-diastolic
–
–
–
volume
bradycardia
improved myocardial contraction
a slowing or reduction in the rate of bone loss (walking,
jogging, stair climbing etc.)
Adaptive Responses

VO2max
– Rapid adaptation
– Men
2/3 augmented cardiac output, 1/3 to peripheral adaptations
women form the peripheral adaptations

–
Improved Skeletal muscle
– increase in number and size of mitochondria, enzyme
–
activity and muscle size
Increase in blood flow
Glucose Tolerance
Endurance Training

Endurance exercises stresses the cardiovascular
system.

The American College of Sports Medicine (ACSM)
– % of maximum heart rate
– rating of perceived exertion
Endurance Training

Exercises are continuous, rhythmical, use
large muscle groups, and increase O2
consumption.

The “oldest old” need endurance and strength
training under close supervision.
How do you determine how much
exercise is too much exercise?
 VO2Max is the best guide, but not practical for most situations.
 Target heart rate
– Medication may alter heart rate response.
– Cardiovascular disease may change heart rate guidelines.
 The “Borg Perceived Exertion Scale” - This is a different scale
from the “Borg Shortness-of-Breath Scale”
Testing
Individual Exercise Capacity

Never exceed the person’s approximated, maximum
target heart rate.
– MD present for maximal stress test
– Submaximal tests to assess fitness
See Exercise Testing Guidelines Box 15-3 page 251

Monitor the person closely for respiration, HR, BP,
pulses and signs of undue stress.

Know the patient’s medical history, functional level,
mental status, and precautions.
Testing
Individual Fitness for Exercise


The test should measure the person’s fitness in the
method of the exercise, itself.
Endurance tests
– 6-Minute Walk Test (page 253)
– Chair Step Test (page 253)
Monitor patient

Strength - One repetition maximum (1RM)
– Example, 60% of 1RM for no. of reps
– Use with Borg’s test
Monitor patient
Exercise:
A Guide from the National
institute of Aging
http://www.niapublications.org/exercisebook/index.asp
Go over the exercises found on pages 35-53
Muscle Fatigue and Muscle Endurance
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


Fatigue is the reduced ability of the muscle to achieve the
same level of force output
Endurance is the ability to sustain a force (approx. 50%) for
a period of time
Clinically endurance and fatigue are used synonymously
– If a patient muscle fatigues, then endurance is reduced.
– If a patients endurance is low, the muscle will fatigue
Motivation is an important aspect for both fatigue and
endurance.
Muscle Fatigue
 Muscle fatigue is a common complaint.
– As seen by the inability to maintain ROM
– As seen by quivering and shaking
 The causes of fatigue vary. Lack of muscle strength
is a major contributor.
– The stronger the muscle, the less fatigue
– increasing strength
increases muscle mass,
function
reduces fatigue
– increasing strength, decreases muscle anoxia
Muscle Endurance

Muscle endurance is related to the aerobic
capacity of the muscle, which, in turn, is
related to the number of mitochondria and the
number of type I fibers.

Muscle strength and aerobic condition are
major determinants of muscle endurance.
Tests and Measures of Fatigue
and Endurance

There is no agreement among therapists on one,
valid test.
 Each therapist develops his/her own measure.

Examples
– Fatigue Test
–
How long a “weighted” upper extremity can climb a finger
ladder.
Endurance Test
How long a patient can hold a muscle contraction.
Age-related Changes In The Lung
Pulmonary Changes

Aging lungs are physiologically and
anatomically similar to the lungs of patients
with mild emphysema.

In aging, there is a decrease in lung
compliance and chest wall thickness.
– There are postural changes and calcification of
–
intercostal cartilage.
There is a weakened muscular force.
Pulmonary Changes

Airway size decreases
– The proportion of collapsible airways increases.
– There is a loss of elastic recoil.
– There is decreased air flow.

Deceased diffusion of gases
– After 20 years, gas diffusion declines at a rate of
–
1.47 to 2.03 ml/minute/mmHg/decade
estrogen?
Other Age-related Changes
Aging Changes
Skin
Skin
– The skin wrinkles, looses
–
–
–
–
elasticity and a decline in cell
replacement occurs.
The skin tears and blisters easily.
There is a loss of dermal thickness (20%),
especially in sun-damaged skin.
Skin neoplasms (benign and malignant) increase.
Vitamin D production declines.
Aging Changes
Skin
A gradual decline is seen in:
– Touch (Meissner’s corpuscles)
– Pressure (Pacinian’s corpuscles)
– Temperature (Krause’s corpuscles)
Aging Changes
Eye


Ptosis, wrinkling and loss of orbital fat
Lens- grows during life span, increasing in
density and weight
– There is a progressive decrease in lens elasticity,
–

so that by 40-50 years, you con no longer focus
(presbyopia) and have to use reading glasses.
Corrective lenses
Aqueous humor- Increased introcular
pressure as you age may lead to glaucoma.
Aging Changes
Ears

Hearing loss accompanies aging
– 10% of U.S. population has hearing loss
– 33% of persons 65-75 years have hearing loss
– 50% of persons over 75 have hearing loss

Presbycusis- aging of middle ear
– Ear drum loses elasticity
– Decreased 8th nerve sensitivity due to noise exposure
– Decline in hair cells of the cochlea
– Joints of the bones of the ear become stiff
– Mechanical blockage- earwax, effusion
One note about oral health…
 You do not loose teeth as a result of aging. With proper oral



hygiene and regular dental visits, your teeth will last your entire
lifetime.
Gum disease (periodontal disease) does not occur as a result of
aging. If an older person has trouble, manually, when brushing
and flossing to prevent periodontal disease, there are many oral
hygiene assistive devices available for use by older persons.
If a patient has dentures, the dentures need to be evaluated on
a yearly basis by a dentist and replaced frequently. As gum
tissue changes with aging, dentures will not fit correctly, making
chewing difficult.
Altered salivary flow may necessitate the need for drinking more
frequently when eating. There are also artificial
saliva’s available for use.
The following slides are a quick review of
normal aging and some pathological
conditions associated with aging.
Source: The University or California, Academic Geriatric Resource
Center
Area of Exam
Common Non-pathologic Changes
Common Pathologic Changes
General
appearance
May move more slowly
Kyphosis
Being unkempt
Skin
Wrinkles
Seborrheic Keratoses
Pigmentation
Thinning and/or graying of hair
Actinic keratoses
Skin cancers
Eyes
Arcus senilis
Slower dark adaptation
Presbyopia
Cataract formation
Glaucoma
Macular degeneration
Marked decreased visual acuity
Ears
Cerumen impaction
Marked hearing loss
Area of Exam
Common Non-pathologic Changes
Common Pathologic Changes
Oral Cavity
Yellowing or greying of teeth
Periodontal diseases
Oral mucosal diseases
Dental caries
Altered salivary flow
Neck
Transmitted sclerosis murmur
Carotid bruits
Multinodular goiter
Cardiovascular
exam
S4
Aortic sclerosis murmur
Increased ventricular ectopy
Systolic Hypertension
Aortic Stenosis murmur
Lungs
Rales that clear with cough may be
present in bedbound patients due to
atelectasis.
Rales that do not clear
Abdominal
exam
Enlarged abdominal aorta
Area of Exam
Common Nonpathologic Changes
Common Pathologic Changes
Female GU
exam
Decreased vaginal lubrication
Smaller uterus and ovaries on
bimanual exam (often not
palpable)
Male GU exam
Enlarged prostate on exam
Palpable bladder after voiding
Neurologic
exam
Frontal release signs
Decreased vibratory sense in toes
More difficult to elicit ankle jerks
Mild increase in leg tone or rigidity
Mild difficulty with word finding
Decreased arm swing and
increased lateral sway
Shorter stride length
Asymmetric exam
Musculoskeletal
exam
Mild loss of strength common
(patient should be able to get out of
chair)
Loss of function due to weakness
Kyphoscoliosis
Decreased joint ROM
Joint deformities
Aging of the Organ Systems
The End
Next time we will look at the skeletal
system and osteoporosis.