physiology of aging “age is an issue of mind over matter. if you don't mind, it doesn't...

PHYSIOLOGY OF AGINGPHYSIOLOGY OF AGING

“Age is an issue of mind over matter.If you don't mind, it doesn't matter." Mark Twain

(1835-1910)

SO

“You're Only As Old As You Feel”

AGING PROCESSAGING PROCESS• Normal Part of Life.

• Begins around ……..

age 30.

“If I'd known I was gonna live this long, I'd have taken better care of myself.”

Eubie Blake (1883-1983) American Jazz Musician

Changes in Physiology with Changes in Physiology with AgingAging

• Older people may exhibit no changes in baseline function, but may have decreased ability to adapt to stress.

• Various body systems lose reserve capacity with aging at different rates.

“I am sick of all this nonsense about beauty being only skin deep.

That’s deep enough. What do you want, an adorable pancreas?”

Jean Kerr

Factors affecting aging of facial featuresFactors affecting aging of facial features

<18.5 = Underweight18.5-24.9 = Normal25-29.9 = Overweight30 or more = Obesity

Smoking

Exposure to sun

Use of alcohol

BMI

BMI = kg/m²

““O” Complex of Geriatric MedicineO” Complex of Geriatric Medicine

Changes in Physiology with Changes in Physiology with AgingAging

• Decreased Homeostasis.

• Older people may exhibit no changes in baseline function, but may have decreased ability to adapt to stress.

• Various body systems lose reserve capacity with aging at different rates.

Changes in Vision and HearingChanges in Vision and Hearing

Significant visual & hearing impairment is present in up to 75% of elderly people

– Often not reported to the physician – May limit ability to function – May lead to social isolation – May interfere with ability to communicate – May appear demented

For older people this means:For older people this means:

• Sensory Deprivation

• Increased risk for falls

• Decreased quality of life

Vision Vision

EyesEyes

– Loss of fat – sunken appearance; eye bags

– Presbyopia

– Slower adaptation to darkness

– Diminished tolerance to glare

– Increasing impairment to colour discrimination

– Increased lens density

– Macular degeneration

– Degeneration of tear gland

SYMPTOMSSYMPTOMS

• Cannot get glasses clean

• Difficulty night driving

• Difficulties reading

• Double vision (in one eye)

Normal LensNormal Lens

CataractCataract

What is your vision like with What is your vision like with cataract?cataract?

Monet’s painting - BeforeMonet’s painting - Before

Monet’s painting - WithMonet’s painting - With

GlaucomaGlaucoma זווית פתוחה זווית פתוחה

Age-Related Macular DegenerationAge-Related Macular Degeneration

Risk factors for AMDRisk factors for AMD

• Increased age

• Female gender

• Lighter iris color

• Race

• Smoking

• Sunlight Exposure

Diabetic NeuropathyDiabetic Neuropathy

Hearing LossHearing Loss

EarsEars

– Loss of elasticity in inner ear leading to loss of high frequency hearing.

– Sounds from speech is distorted due to poor quality amplification

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Changes in Auditory and Visual Changes in Auditory and Visual Function with AgeFunction with Age

• Sensorineural hearing loss – presbycusis.

• Conductive hearing loss may also occur.

• The lens decreases its elasticity and becomes less mobile.

• Cataracts may develop.

• Loss of fat in the eyelids and reduced tone of the levator muscle causes drooping (ptosis) of the eyelid.

Overview of Hearing LossOverview of Hearing Loss

• 60% of elderly over 65 have some degree of hearing impairment.

• 90% of people over 75 have some degree of hearing impairment!

• 75% of all people with hearing loss could benefit from an appropriate hearing aid.

Signs of Hearing LossSigns of Hearing Loss

• Ringing or buzzing in the ears• Talking louder than necessary• Turning up volume on the TV or radio• Complaints that other people “mumble”• Confusion of similar sounding words• Watching a speaker’s face intently• Difficulty “hearing” someone behind you• Having difficulty on the telephone• Inappropriate responses in conversation

Changes in Vision and HearingChanges in Vision and Hearing

• Significant visual, hearing impairment is present in up to 75% of elderly people – These problems are often not reported to the

physician – May limit ability to function – May lead to social isolation – May interfere with ability to communicate – patients with sensory impairments may

appear demented

For older people this means:For older people this means:

• Sensory Deprivation

• Increased risk for falls

• Decreased quality of life

Changes in HeartChanges in Heart

Cardiac Output (CO) = Stroke Volume (SV) x Heart Rate (HR)

The Cardiac CycleThe Cardiac Cycle

Cardiac Cycle

Changes in Cardiovascular Changes in Cardiovascular PhysiologyPhysiology

• Changes in cardiac output (CO): – Maximal heart rate decreased with aging (max. heart rate = 220 - age) – Increased end-diastolic and end-systolic left ventricular volumes

• Diastolic dysfunction – Decreased early diastolic filling – Increased reliance on atrial contraction – Increased vulnerability to congestive heart failure, especially with atrial fibrillation

• Decreased compliance of peripheral blood vessels – predisposes to systolic hypertension, left ventricular hypertrophy of heart

• Increased incidence of atherosclerotic cardiovascular disease

• Increased incidence of degeneration of cardiac conduction system

Cardiovascular System

• The resting cardiac output can remain stable with conditioning exercise in the absence of disease however the output with exercise will be reduced even in healthy aging.

Disease PresentationDisease Presentation• Atypical symptomatology

- Chest pain less frequent- Exertional dyspnea or fatigue more common- ‘Gastrointestinal’ symptoms more common- Confusion, dizziness, other CNS symptoms

• Non-diagnostic ECG due to co-founding factors

• Most MIs are Non ST Elevation MI

For older people this means:For older people this means:

• Decrease in capacity to cope with the demands of physical activity.

• Simple daily tasks become less achievable.

Changes in Pulmonary Changes in Pulmonary PhysiologyPhysiology

Changes in Pulmonary Changes in Pulmonary PhysiologyPhysiology

• Decreased elasticity – Decreased vital capacity – Increased residual volume

• Decreased structural support for small airways – Decreased number of small airways open

during normal breathing

For older people this means:For older people this means:

• Poor effort tolerance

• Greater susceptibility to infections• Pneumonia• TB• Viral Infections

• Difficulty to differentiate between ageing process and environmental damage

Respiratory SystemRespiratory System• Reduced - Lung surface area

- Alveolar elasticity - Forced Expiratory Volume (FEV 1)

- Maximal Oxygen Consumption (VO2 max) - P O2 • Increased - Chest wall stiffness

Osteoporosis and kyphosis can reduce the thoracic capacity. That and alveolar stiffness leads to “senile emphysema” with an FEV1/FVC < 70% of the predicted for age and gender

50

Respiratory functionRespiratory function

• Alveolar function unchanged with age

• Noticable change is reduction in lung compliance

• Also loss of elasticity and reduction in strength of muscles of rib cage reduces usable lung capacity to 82% maximum value by age 45; 62% at age 65; and 50% at age 85

• Over time some alveoli replaced by fibrous tissue

• Gas exchange reduced

• Main problems arise with increased demand (exercise)

SMOKINGSMOKING

Never smoked

Stopped at 45y

Smoker

Stopped at 65y

Renal System

– Loss of diurnal excretory pattern increasing nocturia

– Loss of nephrons

– Reduced plasma blood flow and GFR

– Serum Creatinine will not reflect the GFR as the muscle mass is reduced.

Changes in Changes in Renal/Fluid/ElectrolytesRenal/Fluid/Electrolytes

• Decreased glomerular filtration rate, renal blood flow, creatinine clearance.

• Decreased adaptive mechanisms: – Decreased salt conservation – Increased risk of volume depletion – Increased risk volume overload with saline

• Decreased free water conservation – Decreased maximal urine concentration

• Decreased sense of thirst

Aging and RBFAging and RBF

20 50 80

Age

600

ml/min

300

Note: Arterial collagen deposition increases with age; there is gradual cortical glomerular scarring

Aging and GFRAging and GFR

20 50 80

Age

150

ml/min

75

Note: Glomerular filtration pressure autoregulation is less effective in the elderly

Changes in Fluid & Electrolytes

• Relative excess of antidiuretic hormone (ADH)

• Alterations in renal potassium handling 

For older people this means:For older people this means:

• Possible Water intoxication

• Hyperkalemia

• Increased risk for dehydration

• Increased drug toxicity

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Renal functionRenal function

• Vessels supplying nephrons can become atherosclerotic• Fall in GFR may occur• Affect kidneys ability to excrete metabolites and drugs• At age 80, reduced to 50%• Consequences on homeostasis (eg)• Main problem is reduced ability to respond to salt load

or depletion• Acid base balance• Urinary incontinence

Musculoskeletal ChangesMusculoskeletal Changes

• Decrease in muscle weight relative to total body weight

• Changes in water content of cartilage

• Bone loss in both sexes but more pronounced in women

For older people this means:For older people this means:

• Chronic pain

• Decrease in functional ability contributing to morbidity

• Lack of independence leading to decreases in quality of life

Neuromuscular Neuromuscular

• Reduced propioceptive information

• Delayed nerve conduction

• Reduced numbers of motor neurons

• Reduced fast twitch fibers

• Reduced muscle mass

For older people this means:For older people this means:

Plan simple movement tasks Longer transition times Lots of verbal and visual cues Functional moves.

Changes in Strength with Aging

• Opening the cap on a jar:

– Completed by 92% of men and women between 40 – 60 years of age

– Completed by 32% of men and women between 71-80 years of age

The Digestive SystemThe Digestive System

Motility Secretion Absorption

• General decrease in taste due to

decreased central sensation.

• Decreased salivary volume.

• Formation of fissures and furrows on the

tongue.

Age Related Changes of TasteAge Related Changes of Taste

Gastrointestinal System:Gastrointestinal System:

• Smooth muscle contraction diminished.

• Deterioration of structures in mouth common.

• Decline in efficiency of liver.– Reduced ability to aid in digestion and metabolism of certain

drugs

• Impaired swallowing.– Stomach sphincter valve loss.

• Decrease in nutrient absorption.

For older people this means:For older people this means:

• Constipation is common.

• Poor fitting dentures.

• Increase in heartburn.

• Malnutrition due to deterioration of small intestine.

Standard eating environmentStandard eating environment

Improved eating environmentImproved eating environment

“The secret of staying young is to live honestly, eat slowly, and…….

lie about your age.”

Lucille Ball