3) Justification An acute exercise bout prior to induction of a myocardial infarction in animals provides cardioprotective benefit by reducing the size of the infarct relative to control animals. Recently, acute exercise performed 24 hours before anthracycline injection in rodents has also provided a cardioprotective benefit. Oxidative stress and apoptosis of cardiomyocyte mitochondria are primary mechanisms of anthracycline-induced cardiotoxicity. The single acute bout of exercise prevented or attenuated some of the anthracycline-induced negative effects on cardiomyocytes including oxidative stress, apoptosis, mitochondrial dysfunction, as well as systolic dysfunction. There are no studies to date that have investigated the cardiac effects of an acute bout of exercise in close proximity to anthracycline infusion in humans. Aerobic exercise training is recommended throughout chemotherapy treatment, but there are no guidelines in place in terms of the timing of exercise in relation to receipt of chemotherapy infusions.