Exercise Capacity

Question 1

Why is ventilation uneven across the lungs?

Answer 1

Better ventilation at bottom
1. Pleural pressure less negative down lung
2. Transmural pressure gradient dec down lung
3. Alveolar small down lung —> more compliant
- direction of gravity —> stretch at top

Question 2

Why is intravascular pressure uneven across the lungs?

Answer 2

Better perfusion at bottom
1. Recruitment inc down lung
2. Resistance dec down lung
3. Flow rate inc down lung
- direction of gravity —> stretch at top

Question 3

What is the pattern of lung ventilation/perfusion at rest?

Answer 3

Top:
- alveolar P > arterial P > venous P
- ventilation > perfusion —> blood limits gas exchange

Middle:
- arterial P > alveolar P > venous P
- ventilation = perfusion —> even balance

Bottom:
- arterial P > venous P > alveola P
- ventilation < perfusion —> O2 limits gas exchange

Question 4

What is the pattern of lung ventilation/perfusion during exercise?

Answer 4

V/Q exponential increase from base to apex
- base —> near 0
- apex —> v high

Question 5

Which 4 factors increase ventricular contraction during exercise?

Answer 5

Inc stroke volume:
1. Inc venous return

Inc heart rate:
2. Inc contraction rate - chronotropic effect
3. Inc conduction velocity - dromotropic effect
4. Inc contraction force - ionotropic effect

Question 6

What is exercise?

Answer 6

Purposeful activity involving gross muscular activity to improve physical health

Question 7

What is physical activity?

Answer 7

All muscular activities

Question 8

What are activities of the daily living?

Answer 8

Day-to-day basic self-care tasks

Question 9

Which 3 tests evaluate exercise capacity?

Answer 9

1. Cardiopulmonary test
2. Six-minute walk test
3. Incremental shuttle walk test

Question 9

What is the cardiopulmonary test?

Answer 9

Test:
- Patient on cycle ergometer/treadmill
- Intensity increased incrementally
- Record - ECG
- ventilation
- O2
- CO2
—> find VO2
- Use 9-panel chart

Advantages:
- quantitative
- precise
- reproducible
- safe

Disadvantages:
- skilled technical support needed
- expensive
- need dedicated space

Question 10

What is the six-minute walk test?

Answer 10

Test:
- Time how many times a patients can
walk up and down a corridor (20-30m)
in 6 minutes
- Record total distance walked

Advantages:
- patient-driven pace
- cheap
- validated in many populations

Disadvantages:
- need unobstructed course
- pace not regulated

Question 11

What is the incremental shuttle walk test?

Answer 11

Test:
- Patient on 10m circuit
- Audio recording plays every minute
- Must do 1 more length every minute
ie. min 1 —> 3 lengths, min 2 —> 4
- Record total distance walked

Advantages:
- cheap
- external pacing helps patients reach
maximum
- validated in many populations

Disadvantages:
- need unobstructed course
- some find difficult to start so slow
- patient must manage pace according
to program