Ageing

Question 1

What percentage of muscle power is lost each decade of life?

Answer 1

20-30%/decade

Question 2

What percentage of strength is lost each decade?

Answer 2

10%/decade over 30 years of age

15%/decade over 60 years of age

Question 3

What percentage of 55-64 year olds are unable to lift 4.5kg?

Answer 3

40%

Question 4

What percentage of 75-84 year olds are unable to lift 4.5kg?

Answer 4

65%

Question 5

What percentage of over 70 and 80 year olds have sarcopenia?

Answer 5

> 70: approximately 22%

>80: approximately 50%

Question 6

What occurs as a result of sarcopenia?

Answer 6

• Decrease in muscle fibre number
• Decrease in fibre size, particularly type II (fast twitch) fibres
• Decreased type II fibre cross sectional area

Question 7

What occurs at the micro and macrostructural level as a result of sarcopenia?

Answer 7

Microstructure: damage to z bands and myofibrils
Macrostructure: fatty infiltrate of muscle

Question 8

What changes occur to the connective tissues as we age?

Answer 8

• Decreased water content
• Increased number of cross links
• Decreased elastic fibres

Question 9

What is cachexia?

Answer 9

An inexorable decline in muscles (and body) wasting that can not be arrested with nutrition

Question 10

What age-related changes occur in the cardiovascular system?

Answer 10

• Decline in max HR
• Decline in VO2 max
• Stiffer, less compliant vascular tissues
• Loss of cells from SA node
• Reduced contractility of the vascular walls
• Thickened basement membrane in capillary

Question 11

What are the clinical implications of a decline in maximum heart rate and reduced VO2 max due to ageing?

Answer 11

Smaller aerobic workload possible

Question 12

What are the clinical implications of less compliant vascular tissues?

Answer 12

Higher blood pressures and slower ventricle filling time with reduced cardiac output

Question 13

What are the clinical implications of a loss of cells from the SA node due to ageing?

Answer 13

Slower HR and lower HR maximum

Question 14

What are the clinical implications of reduced contractility of the vascular walls due to ageing?

Answer 14

• Slower HR
• Lower VO2 max
• Smaller aerobic workload

Question 15

What are the clinical implications of a thickened basement membrane in capillaries due to ageing?

Answer 15

Reduced arteriovenous oxygen uptake

Question 16

How is an individual’s maximum heart rate calculated?

Answer 16

220 - age

Question 17

What percentage of VO2 max is lost each decade of life after 25 years of age?

Answer 17

5-15%/decade

Question 18

How do lung volumes change with age?

Answer 18

• Increased residual volume
• Increased functional residual capacity
• Decreased vital capacity (decreased inspiratory and expiratory reserve volumes)

Question 19

What may cause an increase in residual lung volume with age?

Answer 19

Reduced chest wall compliance

Question 20

What age-related anatomic and physiological changes occur in the nervous system?

Answer 20

• Loss of myelin
• Axonal loss
• Autonomic nervous system dysfunction
• Loss of sensory neurons
• Slowed response time

Question 21

What is the clinical implication of a loss of myelin?

Answer 21

Slowed nerve conduction

Question 22

What are the clinical implications of axonal loss due to ageing?

Answer 22

Fewer muscle fibres and loss of fine sensation

Question 23

What are the clinical implications of autonomic nervous system dysfunction?

Answer 23

Slower systemic function with altered sensory input

Question 24

What is the clinical implication of a loss of sensory neurons?

Answer 24

Reduced ability to discern hot/cold, pain

Question 25

What is the clinical implication of slowed response time as we age?

Answer 25

Increased risk of falls

Question 26

How much slower is nerve conduction in a 80-90 year old compared to a 20-30 year old?

Answer 26

10ms slower