Inclusion Criteria:

- females between 18 and 75 years of age;

- signed written informed consent;

- willing to take part in the trial and to follow the instructions;

- breast tumour, histologically documented;

- patients for whom a 6-treatment course of adjuvant or neoadjuvant chemotherapy
(3FEC100 +3 taxanes or 6 FEC) +/- radiotherapy+/- Herceptin has been scheduled;

Exclusion Criteria:

- metastatic cancer;

- disability preventing a proper understanding of the instructions for the trial;

- patients who are subject to a court protection, wardship or guardianship order;

- uncontrolled hypertension;

- family history of sudden death in a first-degree relative;

- unstabilised heart disease;

- current treatment with beta-blockers;

- chronic or acute pulmonary disease associated with dyspnoea upon moderate effort;

- uncontrolled thyroid dysfunction;

- uncontrolled diabetes;

- any other serious conditions that are unstabilised,

- disabling or in which physical exercise is contra-indicated;

- unable to attend for follow-up throughout the duration of the study;

- ventricular ejection fraction (VEF) < 50%, pregnancy or suckling.