This study will compare the effects of two different types of training on exercise capacity in women with coronary heart disease (CHD). Participants will be randomized into either the virtual high-intensity interval training (HIIT) or the virtual moderate-to-vigorous intensity continuous training (MICT). After randomization, patients will exercise twice a week, for 12 weeks. The sessions will be conducted virtually. Patients will undergo a maximal exercise test, cardiometabolic indicators (height (cm), body mass (kg), body composition (%), waist circumference (cm) and, resting blood pressure) and complete questionnaires about quality of life, mental health, self-determined motivation, self-efficacy and enjoyment.

Heart disease is a leading cause of death for women. Women who suffer a heart attack are more likely than men to be inactive, have lower fitness, and die in the next year; patients also report poor mental health and quality of life (QoL), and have a greater risk of cardiovascular disease risk factors. This clinical research project is concerned about women with heart disease and how to improve their fitness, mental health, and QoL using a different kind of exercise. Currently, moderate-to-vigorous intensity continuous training, MICT, is the most frequently prescribed for women with heart disease. Unfortunately, this exercise tends to be a burden and is time-consuming. The study aims to test if high-intensity interval training (HIIT, alternating periods of hard exercise and rest) is better than MICT at improving fitness, mental health, QoL, and exercise dedication in women with heart disease. The investigators will recruit 104 women with heart disease. The investigators will first assess the health measures outlined above and then randomly assign people to MICT or HIIT. Both groups will attend virtual exercise sessions 2 days/week for 12 weeks. The MICT group will perform Zumba/movement-based exercise for 35 minutes at an intensity level of 70-85% of their maximal effort. The HIIT group will perform Zumba/movement-based exercise for 25-minutes: this will consist of 4 periods of exercising for 4-minutes at an intensity level of 85-95% of their maximal effort, separated by 3 minutes of rest between each period. The investigators will assess the health measures again after 12 and 26 weeks. The scores for people in the two groups will then be compared. HIIT has never been evaluated as an alternative for MICT in a large women-only group with heart disease. If this clinical trial shows that HIIT helps these women improve their physical and psychosocial health over usual practice, then health care professionals caring for women with heart disease will have an alternative, effective treatment option to provide women in need.

Inclusion Criteria:

1. Women (i.e., female sex assigned at birth) with CHD (e.g., coronary artery bypass grafting surgery [CABG], percutaneous coronary intervention [PCI], acute myocardial infarction [MI], MI with no obstructive coronary artery disease [MINOCA], or ischemia with no obstructive coronary artery disease [INOCA] at least 4 weeks post procedure or event; based on clinical evidence this is a safe period of time to exercise);
2. Patient is able to perform a symptom limited CPET (this is the primary outcome and needed to determine peak HR for the exercise training prescription); and
3. Patient is able to read and understand English or French.

Exclusion Criteria:

1. Patient is currently participating in routine exercise training (>2x/week, routine exercise training is defined as a planned, structured, and repetitive exercise that is performed in order to maintain or improve physical fitness.) (this may reduce the impact of HIIT or MICT on outcomes);
2. Patient has: NYHA class III-IV heart failure symptoms; unstable angina; or established diagnosis of chronic obstructive pulmonary disease, severe mitral or aortic stenosis, or hypertrophic obstructive cardiomyopathy (this may interfere with the ability to engage in MICT or HIIT);
3. Patient has uncontrolled arrhythmia (this may impact the HR-based exercise training prescription and monitoring);
4. Patient is unable to provide written informed consent; or
5. Patient is unwilling or unable to return for follow-up visits at 12 and 26 weeks.
6. Patient is unwilling to be randomized to HIIT or MICT.

Participants whose gender identity may differ from their birth-assigned sex (female) will be considered eligible for the study