Introduction to Ageing

Question 1

What is the difference between strength & power?

Answer 1

• Strength: Tension generation (cross section size) & moment arm length
• Power: Product of force (strength) & velocity

Question 2

What percentage of strength is lost per decade above 30 yrs and 60 yrs?

Answer 2

> 30 yrs: 10%/decade

>60 yrs: 15%/decade

Question 3

According to the Framington study, what % of 55-64 year old females are unable to lift 4.5kg?

Answer 3

40%

Question 4

According to the Framington study, what % of 75-84 year old females are unable to lift 4.5kg?

Answer 4

65%

Question 5

What is sarcopenia?

Answer 5

• Muscle wasting of old age
• > 2SD below young adult mean measured on DEXA
• 22% of >70yos
• 50% of >80yos (M>W)

Question 6

What is the physiology of sarcopenia?

Answer 6

• Decreased fibre number & fibre size (atrophy), esp. fast twitch (II)
• Damage to z bands & myofibrils (microstructure)
• Fatty infiltrate of muscle (macrostructure)
• Type II fibre cross sectional area reduction up to 50% at age 80

Question 7

What are some of the age-related changes to connective tissues?

Answer 7

• Decreased H2O content
• Increase in cross links (stiffer)
• Decreased elastic fibres

Question 8

What are the clinical implications of changes to connective tissues?

Answer 8

• Need to work into end of range
• Consider role of plyometrics
• Increased apparent strength
• Skin becomes more fragile, translates to tendons, ligaments & internal organs
• Rising closing capacity

Question 9

What is cachexia?

Answer 9

• Decline in muscles & body wasting that cannot be helped with nutrition or exercise
• Associated with AIDS, TB, infection
  Precedes death, associated with COPD & CHF

Question 10

What are the anatomical & physiological C/V changes with age?

Answer 10

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

Question 11

What are the consequences of C/V age-related changes?

Answer 11

• Smaller aerobic workload possible
• Higher BP
• Slower ventricle filling time
• Reduced CO
• Slower HR
• Reduced arteriovenous O2 uptake

Question 12

How does VO2 max change with age?

Answer 12

• Decreases by 5-15% per decade after 25yrs

- Causes decreased CO, arteriovenous O2, max HR, stroke volume

Question 13

How does lung function change with age?

Answer 13

• Higher RV
• Lower VC
• Lower IRV & ERV

Question 14

What are the major age-related changes to nerves?

Answer 14

• Loss of myelin
• Axonal loss
• ANS dysfunction
• Loss of sensory neurons
• Slowed response time

Question 15

What are the consequences of nervous system age-related changes?

Answer 15

• Slowed nerve conduction
• Fewer muscle fibres
• Loss of fine sensation
• Slower systemic function with altered sensory input
• Reduced ability to discern hot/cold, pain
• Increased risk of falls

Question 16

How can aerobic exercises slow neurological decline?

Answer 16

By preventing brain hypoxia caused by poor C/V

Question 17

What is the cause of disability with old age?

Answer 17

Physical decline from inactivity

• Causes sarcopenia
• Decreased balance, strength, endurance, power, nervous system speed
• 50% of >85yo dependent on help