5.9 - Exercise capacity

Question 1

Define exercise

Answer 1

Purposeful, structured activity that involves gross muscular activity to improve physical condition (e.g. jogging, stretching)

Question 2

Define physical activity

Answer 2

A holistic term that includes all (purposeful and incidental) muscular activity of all intensities (walking, stairs)

Question 3

Define activities of daily living

Answer 3

Basic independent self-care tasks done on a daily basis that require coordination, strength and range of motion

Question 4

What body systems are involved in exercise (4)? (look at diagram on slides)

Answer 4

• neurological - motor control, coordination
• respiratory - ability for lungs to ventilate, pulmonary perfusion, gas exchange between lungs and blood
• cardiovascular - ability for heart to receive blood from lungs and to pump to working muscles
• musculoskeletal - local perfusion, muscle cell enzymes

Question 5

How can you evaluate exercise capacity in a clinical population? (3)

Answer 5

• cardiopulmonary exercise test
• six-minute walk test
• incremental shuttle walk test

Question 6

What does the cardiopulmonary exercise test involve?

Answer 6

• uses a cycle ergometer or treadmill
• intensity is incremental
• undertaken under close clinical supervision in a controlled environment
• ECG, ventilation, O2 and CO2 routinely measured

Question 7

What are the outputs of the cardiopulmonary exercise test?

Answer 7

• lots of data
• peak VO2 usually the primary outcome (volume of O2 delivered and utilised)
• ECG changes monitored throughout

Question 8

What are the advantages of the cardiopulmonary exercise test? (3)

Answer 8

• quantifies performance in relation to metabolism
• precise and reproducible
• continuous monitoring for safety

Question 9

What are the disadvantages of the cardiopulmonary exercise test? (3)

Answer 9

• requires skilled technical support (calibration)
• very expensive (initial and ongoing costs)
• needs dedicated space

Question 10

What does the six-minute walk test involve?

Answer 10

• use a 20-30m flat course e.g. corridor
• objective is to cover greatest distance possible in six minutes
• externally timed by assessor
• sub-maximal test

Question 11

What are the outputs of the six-minute walk test?

Answer 11

• primary outcome is total distance walked in 6 mins
• secondary variables may be ‘perceived exertion’ scales, heart rate and pulse oximetry

Question 12

What are the advantages of the six-minute walk test? (3)

Answer 12

• patient-driven pace - speeding up, slowing down and rest is okay
• cheap to deploy
• validated in many clinical populations

Question 13

What are the disadvantages of the six-minute walk test? (2)

Answer 13

• requires a significant unobstructed course - often undertaken in public hospital corridor (obstructions and people)
• pace is not reregulated

Question 14

What is involved in the incremental shuttle walk test?

Answer 14

• uses a 10m circuit
• externally paced by an audio recording (like bleep test)
• each minute has one extra length than the previous minute e.g. minute 1 = 3 lengths of 20s, minute 2 = 4 lengths of 15s

Question 15

What are the outputs of the incremental shuttle walk test?

Answer 15

• primary outcome is total distance walked before volitional end
• secondary variables may be ‘perceived exertion’ scales, heart rate and pulse oximetry

Question 16

What are the advantages of the incremental shuttle walk test? (3)

Answer 16

• cheap to deploy
• validated in many clinical populations
• external pacing helps some to achieve maximal levels

Question 17

What are the disadvantages of the incremental shuttle walk test? (4)

Answer 17

• requires unobstructed course - often undertaken in public hospital corridor
• for some the incremental nature is difficult (min speed 1.8km/hour)
• ceiling effect of 1020m (some can go above this)
• patient can be penalised for poor pace management