Exercise Prescription for CR & PR (Part 2)

Question 1

What is HIIT training?

Answer 1

• Alternating period of intensive exercise (>90% VO2 max) with periods of passive or mod/mild intensity (<40% VO2 max)

Question 2

What are the benefits of HIIT training in cardiac populations?

Answer 2

• Maintain high intensity for longer
• Greater training stimulus
• Increases peak O2 uptake
• Changes in ventricular & endothelial function
• Improves QOL

Question 3

What did Guiraud et al 2012 find regarding HIIT training in CR?

Answer 3

• Stable CAD: Safe, well tolerated, increases exercise length
• HF: Safe, well tolerated, improved adherence & motivation

Question 4

What did Currie et al 2013 find regarding HIIT training in CR following recent CAD event?

Answer 4

• Compared HIIT to MICE
• Both improved brachial artery flow-mediated dilation & peak VO2
• No difference between interventions
• HIIT required less time (common barrier)

Question 5

What did Rognmo et al 2012 find regarding HIIT training in CR?

Answer 5

• Risk of CV event low after HIIT and MICE in CR setting

- HIIT should be considered more in patients with CHD

Question 6

What did Moholdt et al 2014 find regarding HIIT training in CR?

Answer 6

Exercise intensity is an important determinant of improving VO2 peak in patients with CHD (> intensity = > benefits)

Question 7

What did Aamot et al 2012 find regarding HIIT training in CR?

Answer 7

• Exercise mode is not essential for improving exercise capacity
• Home-based may be an option for low-mod risk patients with CAD

Question 8

What did Koufaki et al 2012 find regarding HIIT training in CR?

Answer 8

HIIT is feasible & well-tolerated but not more effective than MICE

Question 9

What are the key features of HIIT established by the research?

Answer 9

• Max exercise test performed pre-program
• Optimal medical treatment &/or undergo re-vascularisation (stable)
• Supervised program with staff trained to handle medical emergencies
• Improves patient adherence & motivation
• Intensity matter

Question 10

What factors contribute to ventilatory limitation of exercise in COPD patients?

Answer 10

• Dynamic hyperinflation & airway obstruction
• Max expiratory flow rate reached during exercise
• Causes further gas trapping
• Increased FRC
• Inspiratory capacity reaches TLC
• Inability to increase TV
• Increased RR & dead space ventilation
• Alveolar ventilation & impaired gas exchange

Question 11

What are the causes of dyspnoea during exercise in COPD patients?

Answer 11

• Dynamic hyperinflation causes restriction of TV
• Altered respiratory mechanics: Increased loading & length-tension properties of respiratory muscles causes fatigue
• Impaired gas exchange (increased PaCO2, decreased PaO2)

Question 12

What happens when COPD patients reduce their activity levels due to dyspnoea?

Answer 12

• Peripheral muscle deconditioning
• Decreased oxidative capacity
• Early onset lactic acidosis during exercise
• Increased CO2 production & ventilator drive

Question 13

What are the causes of CV limitations to exercise in COPD patients?

Answer 13

• Increased pulmonary vascular resistance
• Decreased right ventricular stroke volume
• Can lead to right-sided heart failure

Question 14

What are the causes of skeletal muscle limitations to exercise in COPD patients?

Answer 14

• Decreased oxidative capacity
• Decreased CSA & strength
• Altered muscle composition
• Myopathy due to hypoxia, inflammatory mediators

Question 15

What other mechanisms can limit exercise capacity in COPD patients?

Answer 15

• Nutritional impairments

- Psychological factors