Physiology of Aging

Question 1

Strength

Answer 1

Maximal force exertion
- amount of muscle mass
- ability to recruit muscle mass
- iso/con/ecc muscle actions

Question 2

Power

Answer 2

work/time
- fast and explosive muscle actions
- rate at which something works

Question 3

muscle strength and power

Answer 3

• STR decrease ~40yrs, fast decline after 65-70yrs
• lower body STR decrease faster than upper body STR
• power decreases faster than strength
• deficits in str and power predict disability in old age and mortality risk
• mostly due to sedentary behaviour

Question 4

Sarcopenia

Answer 4

Age related decline in lean body mass that affects functional capacity of OA
- 22-53% of OA develop sarcopenia
-type 1 fibers show little change w age
- type 2 show 25-50% reduction in number and size of fibers

Question 5

Balance and mobility

Answer 5

Sensory, motor, cognitive changes alter biomechanics which can adversely affect balance and mobility
- increase fear of falling and reduce ADL

Question 6

Motor performance and control

Answer 6

• increase reaction time (slower)
• speed of movement decreases
• complex tasks affected more than simple
• impact ADL, risk of injury, task learning time

Question 7

flexibility and joint ROM

Answer 7

• decrease hip, spine, ankle flexion by age 70
• muscle and tendon elasticity decrease
• may increase risk of injury, falling, back pain

Question 8

Cardiac function

Answer 8

• Max HR, SV, Q all decline
• major determinant of reduced exercise capacity w aging

Question 9

vascular function

Answer 9

• Aorta and major branches stiffen
• increase risk of CVD

Question 10

Blood pressure

Answer 10

• BP at rest (systolic) increases
• BP during submax and max exercise is higher in OA
• increase SBP = increase work of heart

Question 11

ventilation

Answer 11

• chest wall stiffens
• expiratory muscle strength decreases
• OA adopt diff breathing strategy during exercise
• increase work of breathing
• pulmonary aging not limiting exercise capacity

Question 12

Max 02 uptake

Answer 12

• decrease 9% per decade in healthy sedentary adults
• rate of decrease accelerated w advancing age
• functional reserve decreases; disease/mortality risk factor

Question 13

V02 Max

Answer 13

VO2 = Q x (a-VO2 diff)
- Q = HR x SV (both max’s decrease 0.7bpm and 10-20%)
- a-VO2 diff: peripheral O2 extraction decrease 5-10%

Question 14

Minimal aerobic capacity

Answer 14

males need 5 METS (17.5ml/kg/min)
women need 4.3 METS (15ml/kg/min)
- healthy sedentary OA >75 has VO2 of 2-4 METS
- healthy sedentary OA <75 has VO2 of 5-7 METS

Question 15

walking kinematics

Answer 15

• prefer slower pace
• stride is shorter, double limb strength is longer

Question 16

Stair climbing ability

Answer 16

• Max step height is reduced
• implications for mobility and physically demanding ADL

Question 17

height

Answer 17

• decrease 1cm per decade in 40s and 50s, accelerate after 60
• vertebral changes can impair mobility

Question 18

weight

Answer 18

• weight steadily increases during 30s-50s, stabilizes, then decrease after 70
• age related changes in WT and BMI can mask fat gain / muscle loss

Question 19

fat-free mass (FFM)

Answer 19

• declines 2-3% per decade from 30-70yrs

Question 20

muscle mass and size

Answer 20

• total muscle mass decrease from age 40
• accelerated after 65-70yrs
• decrease muscle speed and power

Question 21

regional adiposity

Answer 21

• Body fat increase in 30s-50s
• preferential accumulation in visceral region (intra-abdominal)
• after 70 all fat stores decrease
• accumulation of visceral fat linked to CV and metabolic diseases

Question 22

bone density

Answer 22

• bone mass peaks mid-late 20s
• BMD declines 0.5% or more after 40yrs
• women lose 2-3%/yr after menopause
• increases risk of #