Ageing Flashcards
What percentage of muscle power is lost each decade of life?
20-30%/decade
What percentage of strength is lost each decade?
10%/decade over 30 years of age
15%/decade over 60 years of age
What percentage of 55-64 year olds are unable to lift 4.5kg?
40%
What percentage of 75-84 year olds are unable to lift 4.5kg?
65%
What percentage of over 70 and 80 year olds have sarcopenia?
> 70: approximately 22%
>80: approximately 50%
What occurs as a result of sarcopenia?
- Decrease in muscle fibre number
- Decrease in fibre size, particularly type II (fast twitch) fibres
- Decreased type II fibre cross sectional area
What occurs at the micro and macrostructural level as a result of sarcopenia?
Microstructure: damage to z bands and myofibrils
Macrostructure: fatty infiltrate of muscle
What changes occur to the connective tissues as we age?
- Decreased water content
- Increased number of cross links
- Decreased elastic fibres
What is cachexia?
An inexorable decline in muscles (and body) wasting that can not be arrested with nutrition
What age-related changes occur in the cardiovascular system?
- 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
What are the clinical implications of a decline in maximum heart rate and reduced VO2 max due to ageing?
Smaller aerobic workload possible
What are the clinical implications of less compliant vascular tissues?
Higher blood pressures and slower ventricle filling time with reduced cardiac output
What are the clinical implications of a loss of cells from the SA node due to ageing?
Slower HR and lower HR maximum
What are the clinical implications of reduced contractility of the vascular walls due to ageing?
- Slower HR
- Lower VO2 max
- Smaller aerobic workload
What are the clinical implications of a thickened basement membrane in capillaries due to ageing?
Reduced arteriovenous oxygen uptake
How is an individual’s maximum heart rate calculated?
220 - age
What percentage of VO2 max is lost each decade of life after 25 years of age?
5-15%/decade
How do lung volumes change with age?
- Increased residual volume
- Increased functional residual capacity
- Decreased vital capacity (decreased inspiratory and expiratory reserve volumes)
What may cause an increase in residual lung volume with age?
Reduced chest wall compliance
What age-related anatomic and physiological changes occur in the nervous system?
- Loss of myelin
- Axonal loss
- Autonomic nervous system dysfunction
- Loss of sensory neurons
- Slowed response time
What is the clinical implication of a loss of myelin?
Slowed nerve conduction
What are the clinical implications of axonal loss due to ageing?
Fewer muscle fibres and loss of fine sensation
What are the clinical implications of autonomic nervous system dysfunction?
Slower systemic function with altered sensory input
What is the clinical implication of a loss of sensory neurons?
Reduced ability to discern hot/cold, pain
What is the clinical implication of slowed response time as we age?
Increased risk of falls
How much slower is nerve conduction in a 80-90 year old compared to a 20-30 year old?
10ms slower
