Study of Aerobic Training for People Receiving Treatment for Breast Cancer

Inclusion Criteria:

* Aged ≥18 years
* Female
* Diagnosed with primary breast cancer as defined by one of the following:

  * Histological confirmation
  * As per standard of care imaging
* Scheduled to receive neoadjuvant/adjuvant systemic and/or locoregional therapy
* Performing ≤90 minutes of moderate- and/or strenuous-intensity exercise per week, as evaluated by self-report
* Willingness to comply with all study-related procedures
* Able to achieve an acceptable peak baseline CPET, as defined by any of the following criteria:

  1. Achieving a plateau in oxygen consumption, concurrent with an increase in power output;
  2. A respiratory exchange ratio ≥ 1.10;
  3. Attainment of maximal predicted heart rate (HRmax) (i.e., within 10 bpm of age-predicted HRmax \[HRmax = 220-Age\[years\]);
  4. Volitional exhaustion, as measured by a rating of perceived exertion (RPE) ≥ 18 on the BORG scale.

Exclusion Criteria:

* Enrollment onto any other interventional investigational study, except interventions determined by the PI not to confound study outcomes
* Receiving treatment for any other diagnosis of invasive cancer
* Distant metastatic malignancy of any kind
* Mental impairment leading to inability to cooperate
* Any of the following contraindications to cardiopulmonary exercise testing:

  i. Acute myocardial infarction within 3-5 days of any planned study procedures; ii. Unstable angina; iii. Uncontrolled arrhythmia causing symptoms or hemodynamic compromise; iv. Recurrent syncope; v. Active endocarditis; vi. Acute myocarditis or pericarditis; vii. Symptomatic severe aortic stenosis; viii. Uncontrolled heart failure; ix. Acute pulmonary embolus or pulmonary infarction within 3 months of any planned study procedures; x. Thrombosis of lower extremities; xi. Suspected dissecting aneurysm; xii. Uncontrolled asthma; xiii. Pulmonary edema; xiv. Respiratory failure; xv. Acute non-cardiopulmonary disorders that may affect exercise performance or be aggravated by exercise (i.e., infection, renal failure, thyrotoxicosis) xvi. Room air desaturation at rest ≤ 85%
* Any other condition or intercurrent illness that, in the opinion of the investigator, makes the subject a poor candidate for study participation