What is the recommended approach to aerobic exercise for patients with coronary microvascular disease?

Aerobic Exercise Prescription for Coronary Microvascular Disease

Patients with coronary microvascular disease (INOCA/ANOCA) should perform moderate-intensity continuous aerobic training at 40-70% of heart rate reserve for 30-60 minutes, 3-7 days per week, as this is feasible, improves cardiorespiratory function and quality of life, and represents the safest approach for this population. 1

Initial Assessment Requirements

Before starting any exercise program, you must establish:

• Baseline exercise capacity through either a pre-discharge exercise test or 6-minute walk distance to establish safe training parameters 2
• Maximal exercise testing (stress test) is recommended for older adults (men ≥45 years, women ≥55 years) who are starting vigorous training programs 1
• Rate control adequacy during exertion if the patient has atrial fibrillation, as resting heart rate assessment is insufficient 2
• Screening for high-risk cardiovascular conditions that would contraindicate exercise, including refractory/unstable angina, high-grade arrhythmias, decompensated heart failure, severe aortic dilatation, or active thromboembolic disease 1

Specific Exercise Prescription Using the FITT Model

Frequency

• Minimum 3 days per week, preferably 6-7 days per week 1
• Daily exercise may be most effective for cardiovascular benefit 1
• Even 1-2 sessions per week meeting recommended activity levels reduces all-cause mortality (HR 0.66) and cardiovascular mortality (HR 0.60) compared to inactive participants 1

Intensity

• Moderate intensity at 40-70% of heart rate reserve or VO2 max 1
• This can also be prescribed as 50-60% of peak oxygen uptake 3
• Use the Borg Rate of Perceived Exertion (RPE) scale: target 5-6 on the CR10 scale for moderate intensity 1
• Avoid high-intensity interval training initially - while one study showed high-intensity training (80-90% VO2peak) increased aerobic capacity by 17.9% versus 7.9% for moderate intensity 3, and HIIT has relatively low adverse event rates (1 major cardiovascular event per 17,083 training sessions) 4, the 2024 ESC guidelines state there is insufficient evidence to promote HIIT over moderate-intensity continuous training for coronary syndromes 1

Time (Duration)

• 30-60 minutes per session 1
• Can be accumulated in bouts of ≥10 minutes throughout the day 1
• Total weekly volume should be 150-300 minutes of moderate-intensity activity or 75-150 minutes of vigorous-intensity activity 1
• For patients with limited capacity, start with brief 10-minute sessions and add 5 minutes per session until 30 minutes is reached 1

Type (Modality)

• Large muscle group aerobic activities: walking, jogging, cycling, swimming, cross-country skiing 1
• Lifestyle activities also count: brisk walking, climbing stairs, gardening, active recreational pursuits 1
• Avoid activities requiring Valsalva maneuver which can cause acute blood pressure spikes 1

Evidence Specific to Microvascular Disease

Small, single-center studies demonstrate that exercise training in patients with INOCA (ischemia with non-obstructive coronary arteries, which includes microvascular disease):

• Is feasible and safe 1
• Improves cardiorespiratory function 1
• Improves quality of life 1
• However, larger trials are needed to determine optimal rehabilitation protocols and long-term benefits 1

Resistance Training Addition

After establishing aerobic capacity, add resistance exercise:

• 1-3 sets of 8-12 repetitions 1
• Intensity of 60-80% of one-repetition maximum 1
• Frequency of at least 2 days per week 1
• Use 8-10 different exercises involving major muscle groups 1
• Use lower resistance and more repetitions, with proper breathing technique to prevent Valsalva maneuver 1

Mechanisms of Benefit

Exercise training in coronary disease works through four key mechanisms:

• Improvement of endothelial function - directly addresses the pathophysiology of microvascular dysfunction 1
• Reduced progression of coronary lesions 1
• Reduced thrombogenic risk through increased plasma volume, reduced blood viscosity, decreased platelet aggregation, and enhanced thrombolytic ability 1
• Improved collateralization and myocardial perfusion 1

Critical Safety Considerations

Absolute contraindications to exercise:

• Refractory or unstable angina 1
• High-grade arrhythmias 1
• Decompensated heart failure 1
• Severe aortic dilatation 1
• Active thromboembolic disease 1
• Active infection, uncontrolled diabetes, end-stage cancer, or COPD exacerbation 1

Monitoring requirements:

• If on beta blockers, these may attenuate heart rate response and reduce exercise capacity; patients should cool down gradually after exercise to prevent hypotension 1
• Monitor for unusual or persistent fatigue, increased weakness, or symptoms lasting >1 hour after exercise 1

Optimizing Long-Term Adherence

• Maintenance of the prescribed exercise regimen is crucial - the largest reductions in total and cardiovascular mortality occur in patients with the highest adherence rates 1
• Personalize the prescription based on patient preferences (self-selected training) and abilities (age, comorbidities, leisure and working habits, logistical constraints) 1
• Home-based cardiac rehabilitation with or without telemonitoring may increase participation and be as effective as center-based programs 1
• Smartphone applications and wearable activity trackers may assist in long-term adherence to physical activity goals 1
• Phase III cardiac rehabilitation (continuation) is recommended as it maintains functional capacity, quality of life, and physical activity levels 1

Expected Outcomes

Exercise training as part of cardiac rehabilitation in chronic coronary syndromes leads to:

• 26% reduction in cardiac mortality 1
• Reduction in hospitalizations and adverse cardiovascular events 1
• Improved cardiovascular risk profile 1
• Increased exercise capacity and cardiorespiratory fitness 1
• Improved perception of well-being 1
• Each single-stage increase in physical work capacity is associated with an 8-14% reduction in all-cause mortality risk 1