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Age-related Physiological Changes
Dr. Mohammadhossein Soltani,
MD,MPH
Aging Definition Changes
multidimensional process of physical, psychological, and social change Aging is a normal biological/physiologic process (a series of actions or steps taken in order to achieve a particular end) NOT PATHOLOGIC in human beings involving :
Intrinsic affecting by environment (LIFE STYLE) gradual
universal process
spontaneous change
alteration of body structure, function, and tolerance to
environmental stress
Aging Process characterised by
Considerable decreased in function and structure Declining ability to respond to bio-psycho-social stress (FRAILTY) Increasing homeostatic imbalance Increased risk of disease
Physiology & pathology
• • Changes in all people (NORMAL AGING) • Decreased function (NORMAL AGING) Impairment function (DISEASE) • Universal (NORMAL AGING) • Haemostasis imbalance (NORMAL AGING) • Compatible with age (NORMAL AGING) • Not life threatening (NORMAL AGING)
Older People are NOT the Same
Older People are NOT the Same
Older people are a very diverse group in terms of:
• • • • • • • • • •
Gender
Biological Characteristics Ethnic and Cultural background
Climate Geographic locations Family size
Living in developing or developed countries
Life skills and experience
Economic situations Social isolation (being part of family, being part of community or a religious group)
Age-related Physiological Changes
Normal ageing affects all physiological processes Subtle irreversible changes in the function of most organs can be shown to occur by the 3
rd and 4 th
decade of life, with
progressive deterioration with age
The rapidity of the decline in function varies with organ system under consideration but it is relatively constant within a given
system
The distinction that must be made between the normal attrition of function occurring in all persons with advancing age and the loss of function that makes the onset of pathological changes from one or more of the diseases encountered with increased prevalence in older people Failure to recognize this difference can lead to progressive disability from treatable diseases in many cases
Age-related Physiological Changes—longevity
• Several factors affects longevity including:
Heredity
Medical treatment
life style (diet, physical activity)
Biological Aspects of Ageing Changes that occur in ageing I. Changes affecting the cells II. Changes affecting the tissues III. Changes affecting organs IV. Changing affecting the whole body
Biological Aspects of Ageing
Main Factors:
I. Genetic Aspects II. Cell Damage III. Decline in Function IV. Collagen Changes V. Thermoregulatory Mechanism VI. Immune System
Biological Aspects of Ageing
• These changes with age have important practical implications for the clinical management of elderly patients: metabolism is altered changes in response to commonly used drugs make different drug dosages necessary
Genetic Aspects
I.
Genes that promote early ageing such as tumor suppressor II.
Some genes cause disease in early life and decrease longevity such as cystic fibrosis which predisposes to early death III. Genes that cause age- related disease Alzheimer’s disease Hypercholesterolemia Coronary Heart Disease Cerebral - vascular accident Diabetes
Age-Related Changes - Immune System
I.
Ageing attributes to abnormal function of the immune system II.
The Thymus gland atrophy with age (source of T Lymphocytes) III. B-Lymphocytes slightly reduced Immunization against influenza & pneumococcal pneumonia is effective in the elderly- it is recommended
Age-Related Changes
—
Nutrition
Protein, vitamin, and mineral requirements usually unchanged Energy requirements possibly decreased by about 200 calories/day due to decreased activity Diminished absorption of calcium and vitamin B1 and B2 due to reduced pepsin and hydrochloride acid secretion Decreased salivary flow and decreased sense of taste (may reduce appetite) Diminished intestinal motility and peristalsis of the large intestine Brittle (breakable) teeth due to thinning of tooth enamel Decreased biting force Diminished gag reflex Limited mobility (may affect ability to obtain or prepare food)
Age-Related Changes
—
Skin
Facial lines resulting from (1) subcutaneous fat loss, (2) dermal thinning, (3) decreasing collagen and elastin, and (4) 50% decline in cell replacement Delayed wound healing due to decreased rate of cell replacement Decreased skin elasticity (may seen almost transparent) Brown spots on skin due to localized melanocyte proliferation Dry mucous membranes and decreased sweat gland output (as the number of active sweat glands declines) Difficulty regulating body temperature because of (1) decrease in size, number, and function of sweat glands and (2) loss of subcutaneous fat So, skin loses its tone and elasticity
Age-Related Changes
—
Hair
• Decreased pigment, causing gray or white hair • Thinning as the number of melanocytes declines • • Pubic hair loss resulting from hormonal changes Facial hair increase in postmenopausal women and
decrease in men
• • • • • • • • • • •
Age-Related Changes—Eyes and vision
Baggy (loose) and wrinkled eyelids due to decreased elasticity, with eyes sitting deeper in sockets Thinner and yellow conjunctiva; possible pingueculae (fat pads) Decreased tear production due to loss of fatty tissue in lacrimal apparatus Corneal flattening and loss of luster (shine) Fading (loss) or irregular pigmentation of iris Smaller pupil, requiring three times more light to see clearly; diminished night vision and depth perception Scleral thickening and rigidity; yellowing due to fat deposits Vitreous degeneration; revealing opacities and floating debris Lens enlargement; loss of transparency and elasticity, decreasing accommodation Impaired color vision due to deterioration of retinal cones Decreased reabsorption of intraocular fluid, predisposing to glaucoma
Age-Related Changes—Eyes and vision
• • • • Some of the major normal aging changes in the eye that affect vision include (1) Corneal Flattening, (2) Lens Transparency, (3) Less Efficient Retina, (4) Reduced Lens Elasticity ( Presbyopia ). Over time the lens of the becomes less elastic which (1) diminishes the focusing power of the eye and causes a (2) a decline in visual acuity. This changes is usually first noticed around age 40 and is called presbyopia. As presbyopia becomes more pronounced, people hold reading materials further away from their eyes. Some get headaches or "tired eyes" while reading or doing other close work. By age 55, most people require glasses for reading at least part of the time. Those who already wear glasses may need bifocals. Fortunately, only 5% become unable to read and about 20% have enough visual impairment to prevent driving.
Age-Related Changes—Ears and hearing
• • • • • • • • • Atrophy of the organ of Corti and the auditory nerve (sensory presbycusis) Inability to distinguish high-pitched consonants (bi seda) Degenerative structural changes in the entire auditory system People do not seem to speak clearly-- it sounds as if they are mumbling. Background noise makes it even harder to hear. Certain sounds seem loud or annoying. A background hissing or ringing is heard. Social events such as parties, concerts, or watching television are less enjoyable because you can't hear as well. Straining to understand what others are saying.
Age-Related Changes
—
Ears and hearing
•
Diagnosis of Hearing Impairment
Unfortunately, older adults are not routinely screened for hearing loss by health care providers. It is relatively quick and easy to administer a hearing test using an audiometer . This test assesses the
magnitude and pattern of the hearing impairment as well as the
type of hearing loss (e.g., conductive, sensory, or central). •
Treatment
About one in three older adults have their hearing reduced by up to 35% because of the accumulation of (1) ear wax which blocks the sound. This is one of the most treatable causes of hearing loss; health care professionals can remove excess ear wax. Another common cause of hearing loss among older adults is (2) medications, especially antibiotics or diuretics which can cause permanent hearing impairment.
Smell
• As we age, the number of functioning smell receptors decreases and this increases the threshold for smell. It takes a more intense smell for it to be identified and differentiated from other smells. • • • After the age of 50 the sense of smell decreases rapidly. By age 80, the sense of smell is reduced by about half.
The lack of ability to smell spoiled food can lead to indigestion and food poisoning. • Even more seriously, studies have show that older persons may not be able to detect relatively high levels of mercaptoethanol. This odorant is added to natural gas, so that individuals can detect gas leakage. Thus older persons can miss detecting natural gas leakage at levels that could cause explosions.
Taste
•
Taste also diminishes with age
• Older persons often complain that food doesn't taste as good as it used to. • Some atrophy of the tongue occurs with age and this may diminish sensitivity to taste. Receptor cells for taste are found in the taste buds on the tongue and are replaced continuously. • Other factors that contribute to changes in taste among seniors include poorly fitting dentures.
Touch
• In later life, the sense of touch and response to painful stimuli decreases. • The actual number of touch receptors decreases which
results in a higher threshold for touch.
• The major concern a loss in touch sensitivity raises relate to personal safety. For example, older adults do not sense heat as quickly so they tend to have worse burns.
• • • • • • • • • • •
Age-Related Changes—Respiratory System (1)
The respiratory system reflects changes that occur in many other body systems, including the cardiovascular, nervous and musculoskeletal systems. Nose enlargement from continued cartilage growth General atrophy of tonsils Tracheal deviation due to changes in the ageing spine Increased anteroposterior chest diameter as a result of altered calcium metabolism and calcification of costal cartilage Lung rigidity; decreased number and size of alveoli
Kyphosis Respiratory muscle degeneration or atrophy Declining diffusing capacity Decreased inspiratory and expiratory muscle strength; diminished vital capacity
Age-Related Changes—Respiratory System(2)
• Lung tissue degeneration, causing (1) decrease in lungs’ elastic recoil capacity and (2) increase in residual capacity • Poor ventilation of the basal areas (from closing of some airways), resulting in decreased surface area for gas exchange and reduced partial pressure of oxygen • Oxygen saturation decreased by 5% • 30% reduction in respiratory fluids, heightening risk of pulmonary infection and mucus plugs •
Lower tolerance for oxygen debt
• So, impaired gas exchange, a decrease in vital capacity and slower expiratory flow rate
Age-Related Changes—Respiratory System(3)
• The lungs become stiffer, muscle strength and endurance diminish, and the chest wall becomes more rigid. • Total lung capacity remains constant but vital capacity decreases and residual volume increases. • The alveolar surface area decreases by up to 20 percent. Alveoli tend to collapse sooner on expiration.
• There is an increase in mucus production and a decrease in the activity and number of cilia.
Age-Related Changes
—
Cardiovascular System(1)
• • • • • • • • Slightly smaller heart size
Loss of cardiac contractile strength and efficiency
30% to 35% diminished cardiac output by age 70 Heart valve thickening, causing incomplete closure (systolic murmur) 25% increase in left ventricular wall thickness between age 30 and 80 Fibrous tissue infiltration of the sinoatrial node and internodal atrial tracts, causing atrial fibrillation and flutter
Vein dilation and stretching
35% decrease in coronary artery blood flow between age 20 and 60
Age-Related Changes- Cardiovascular System(2) • Increased aortic rigidity, causing increased systolic blood pressure disproportionate to diastolic, resulting in widened pulse pressure • • • • • ECG changes: increased PR, QRS complex, and QT interval; decreased amplitude of QRS complex; shift of QRS axis to the left
Heart rate takes longer to return to normal after exercise
Decreased strength and elasticity of blood vessels, contributing to arterial and Venus insufficiency
Decreased ability to respond to physical and emotional stress
So, (1) decreased output, (2) increases blood pressure, (3) developing arteriosclerosis
Age-Related Changes
—
Cardiovascular System(3)
• The maximum heart rate decreases and it takes longer for heart rate and blood pressure to return to normal resting levels after exertion. • The aorta and other arteries becomes thicker and stiffer which may bring a moderate increase in systolic blood pressure with aging. In some individuals, this may result in hypertension.
• The valves between the chambers of the heart thicken and become stiffer. As a result heart murmurs are fairly common among older adults.
• The pacemaker of the heart loses cells and develops fibrous tissue and fat deposits. These changes may cause a slightly slower heart rate and even heart block. Aberrant heart rhythms and extra heart beats become more common.
• The
baroreceptors
which monitor blood pressure become less sensitive. Quick changes in position may cause dizziness from
orthostatic hypotension.
Age-Related Changes
—
GI System(1)
•
Diminished mucosal elasticity
• Reduced GI secretions, affecting digestion and absorption • Decreased motility, bowel wall and anal sphincter tone, and abdominal wall strength • Liver changes: decreases in weight, regeneration capacity, and blood flow • Decline in hepatic enzymes involved in oxidation and reduction, causing less efficient metabolism of drugs and detoxification of substances •
(1) Decreased motility, (2) atrophic gastritis, (3) altered hepatic drug metabolism
Age-Related Changes—GI System (2)
• • •
Increased prevalence of (1) atrophic gastritis and (2) achlorhydria (decreased production of acid).
The liver is less efficient in (1) metabolizing drugs and (2) repairing damaged liver cells.
•
Diverticuli in the colon may cause pain.
•
Reduced peristalsis of the colon can increase risk for constipation.
Age-Related Changes
—
Renal System (1)
•
Decline in glomerural filtration rate(GFR)
• 53% decrease in renal blood flow secondary to reduced cardiac output and atherosclerotic changes • Decrease in size and number of functioning nephrons •
Diminished kidney size (25% to 35%)
•
Impaired clearance of drugs
• The creatinine clearance decreases with age, although the serum creatinine remains relatively constant due to proportionate (balance) age-related decrease in creatinine
Age-Related Changes
—
Renal System (2)
• • With aging, there is a reduced hormonal response (vasopressin) and an impaired ability to conserve salt which may increase risk for dehydration.
Weakening of bladder muscle, causing (1) incomplete emptying and (2) chronic urine retention • Bladder capacity & size decreases and there is an increase in residual urine and frequency.
These changes increase the chances of urinary infections, incontinence, and urinary obstruction.
Age-Related Changes
—
Male Reproductive System
Reduced testosterone production, resulting in decreased libido as well as atrophy and softening if testes Prostate gland enlargement, with decreasing secretions 48% to 69% decrease in sperm production between ages 60 and 80
Decreased volume and viscosity of seminal fluid
Slower and weaker physiologic reaction during intercourse, with lengthened refractory period
Age-Related Changes
—
Female Reproductive System
Declining Estrogen and Progesterone levels cause: I.
II.
III.
IV.
V.
VI.
VII.
Cessation of ovulation; atrophy, thickening, and decreased size of
ovaries
Loss of pubic hair and flattening of labia majora Shrinking of vulval tissue, constricted introitus, and loss of tissue elasticity Vaginal atrophy; thin and dry mucus lining; more alkaline PH of vaginal environment
Shrinking uterus
Cervical atrophy, failure to produce mucus for lubrication, thinner endometrium and myometrium Pendulous breasts; atrophy of glandular, supporting and fatty tissue
Age-Related Changes—Neurologic System
• • • • • • • • Degenerative changes in neurons of (1) central and (2)
peripheral nervous system Slower nerve transmission
Decrease in number of brain cells by about 1% per year after age 50
Hypothalamus less effective at regulating body temperature
20% neuron loss in cerebral cortex
Slower corneal reflex Increased pain threshold
Decrease in stage III and IV of sleep, causing frequent awakenings; rapid eye movement sleep also decreased
Age-Related Physiologic Changes-Neurologic System • The aging of the central nervous system is often portrayed as an irreversible loss of functions and decline in abilities.
• In the past, scientists reported that we "lose a million neurons every day". Fortunately, that's not correct. The adult brain retains a remarkable plasticity in it's ability to compensate functionally for those losses that do occur. • Further, some cognitive abilities, such as wisdom and life experience, are stable or may increase with age.
• • The weight of brain peaks around age 20 and then a modest decline occurs with age that is limited to the gray matter (outer surface of the brain) in healthy older people.
Age-Related Physiologic Changes-Neurologic System • Older nerve cells may have fewer dendrites (branches) and some may become demyelinated (lose its coating) which can slow the speed of message transmission. Most of these changes do not appear to affect ordinary activities of living.
•
People often fear cognitive decline in later life more than any other
disabling condition. Cognitive ability is crucial to the capacity to live independently. Most of us do not want to be dependent on others as we age. Impairment in cognitive capacity can threaten autonomy
and the ability to manage our daily activities.
Age-Related Physiologic Changes-Neurologic System • • • • •
Attention
The concept of attention involves both sustained attention (i.e., ability to focus) and selective attention (the ability to distinguish relevant from irrelevant information).
Older adults appear to perform tasks requiring sustained attention or selective attention extremely well into old age
.
Language
One aspect of language—
semantic Knowledge
-- appears to decline with age, although significant differences are not found until relatively late in the life span (greater than 70 years). Semantic knowledge involves word retrieval and is tested by having respondents name common objects. • Linguistic abilities that are not affected include phonologic knowledge sounds of language), lexical knowledge of a word), and syntactic knowledge (use of (i.e. the name of an item and the meaning (i.e. ability to combine words correctly).
Age-Related Physiologic Changes-Neurologic System •
Memory
Memory has been more widely studied than almost any other aspect of cognitive function, other than intelligence. • After arthritis, memory problems are the second most frequent complaint among older adults. • From age 45, the overall frequency of complaints of memory problems increases steadily. • The efficiency of memory may differ considerably depending on the situation or context. For example, reliable recall of visual images such as paintings may be accompanied by a relatively poor recall of verbal words.
•
Older adults perform less well on tasks involving encoding, retention, and
retrieval of information.
• • • • • • I.
II.
III.
Age-Related Physiologic Changes-Neurologic System As people grow older, the rate at which they process information declines. Information processing has three phases: encoding : getting information into the system storage: retaining information retrieval : recalling information. Encoding is particularly vulnerable to age. As we age it takes more time to encode information than when they were younger. This slower rate of encoding may be changes in our term memory. vision, hearing and other senses due to that reduce the efficiency of memory. The slower rate of encoding is most likely the reason for age-related declines in short- Two types of memory tasks are recall (retrieving information) and (matching information). Regardless of age, recognition is better than recall. Recognition does not decline as we age, but recall does.
recognition
Long-term memory may decline as we age depending on the extent to difficulty with encoding information.
Very long-term memory which spans months or years is relatively
stable
until well after age 70.
Age-Related Physiologic Changes-Neurologic System •
Visual-Spatial Ability
Older adults show declines in visual-spatial abilities which affect visual tasks such as identifying incomplete figures, recognizing embedded objects, or arranging blocks into a design. Aging also appear to affect both the ability to perceive and the ability to reproduce figures in three dimensions. •
Conceptualization
Mental flexibility and the capacity for abstraction do appear to decline with age however, the greatest age differences appear among those who are seventy or older. •
General Intelligence
In measures of intelligence, older adults display what is called the "classic aging pattern".
Performance scores
which measure
problem solving ability
tend to
decline with age
after age 70.
. Verbal scores which measure learning knowledge such as comprehension, arithmetic, and vocabulary, tend to remain stable. Relatively little decline in performance occurs prior to age 50. Substantial declines appear to occur
Age-Related Physiologic Changes-Neurologic System •
Reaction Time
Tests of reaction time indicate a decline in the processing of information among adults age 40 and older, and that the
more complex the required processing
, the larger the age differences in processing time.
differences represent about 10 seconds difference and are not clinically
detectable. However, in real world terms these • Many of the abilities in which declines occur can be improved through
training practice in (1) memory techniques, (2) problem-solving skills, and (3) other
cognitive strategies.
and
•
Short-term memory loss is common and determining whether "forgetfulness" is benign or a precursor of dementia is often impossible.
skills. The average 70 year old can take up to 4 times longer than a 20 year old in tests involving basic memory • Older adults are also slower in reaction time than younger adults as is clearly shown by the declines in the speed of information processing.
Psychosocial problems
Poor adjustment to role changes Poor adjustment to lifestyle changes Family relationship problems Grief Low self-esteem Anxiety and depression Aggressive behavior Loneliness Isolation Problems with sexuality Elderly abuse Withdrawing and having a negative attitude toward life in gener al
Age-Related Changes—Immune System
• • • • • • • Loss of ability to distinguish between self and nonself Loss of ability to recognize and destroy mutant cells, increasing incidence of cancer Decreased antibody response, resulting in greater susceptibility to infection
Tonsillar atrophy and lymphadenopathy
Lymph node and spleen size slightly decreased Some active blood-forming marrow replaced by fatty bone marrow, resulting in inability to increase erythrocyte production as readily as before in response to such stimuli as hormones, anoxia, hemorrhage, and
hemolysis
Diminished vitamin B12 absorption, resulting in reduced erythrocyte mass and decreased hemoglobin level and hematocrit
Age-Related Changes
—
Musculoskeletal System
• • • • • •
Increased adipose tissue
Decreased lean body mass and bone mineral contents due to loss and atrophy of muscle cells Decreased height from exaggerated spinal curvature and narrowing intervertebral spaces
Decreased collagen formation and muscle mass
Increased viscosity of synovial fluid, more fibrotic synovial membrane Degenerative changes occur in many joints and this, combined with the loss of muscle mass, inhibits elderly patients’ locomotion
Age-Related Changes
—
Endocrine System
• • • • • • • • •
Decreased ability to tolerate stress
Blood glucose concentration increases and remains elevated longer than in a younger adult
Diminished levels of estrogen and increasing levels of follicle-stimulating
hormone during menopause,
causing coronary thrombosis and osteoporosis Reduced progestron production
50% decline in serum aldestrone levels 25% decrease in cortisol secretion rate Progressive elevation of blood glucose and osteoporosis due to a linear
decline in bone mass after the 4 th decade
Insulin resistance may prevent efficient conversion of glucose into energy. A decrease in aldosterone and cortisol may affect immune and
cardiovascular function
Laboratory Value Changes in Elderly Patients
•
Standard normal laboratory values reflect the physiology of adults age 20-40
•
However, normal values of older patients usually
differ because of age-related physiologic changes
•
Certain test results remain unaffected by age
(PTT, PT, serum acid phosphatase, serum carbon dioxide, serum chloride, asparate aminotransferase, and total serum protein)
Laboratory Value Changes in Elderly Patients
Laboratory Value Changes in Elderly Patients
Laboratory Value Changes in Elderly Patients
I.
II.
III.
IV.
V.
Age-Related Physiologic Changes
So, natural ageing is in some way distinct from the onset of age-
associated disease
It is true, that the changes that occur in skin, muscle or hair are NOT
pathologic Ageing causes decreased organ reserve function
Nevertheless, when the process of degeneration we know as ageing affects an essential organ, then it is labeled as a disease Ageing is multicausal, but that the onset of deterioration in tissue and organ function is not fully synchronized, so it is inevitable that
when one system fails in advance of others, it is labeled a disease
Ageing is a
continuous
and
unavoidable
process Ageing
may be retarded
Problems associated with ageing can be managed:
I.
II.
III.
IV.
V.
VI.
Wear glasses Denture High fiber diet, fruits and green vegetables with rich antioxidants Fishes Adequate calcium intake other aids