Cardiotoxicity is one of the most significant adverse effects in breast cancer patients treated with anthracyclines (a type of chemotherapy), so we propose to determine whether acute training (i.e., 24h before each chemotherapy session) could reduce the levels of a cardiac biomarker which measures muscle damage (NT-proBNP). Given the fact NT-proBNP attenuation has been observed with one session performed 24h before the first treatment, we propose to verify these findings in each cycle of doxorubicin analyzing how each type of exercise (aerobic, strength or combined aerobic + strength) may impact on anthracycline-induced cardiotoxicity, since this observation may be relevant considering the feasibility and low cost this implementation would represent in clinical practice.