The American College of Sports Medicine states that 150 minutes per week of moderate aerobic activity improves quality of life, also in patients treated for cancer. Physical activity before, during, and after oncological treatments increases rates of survival, interval free from sickness, and side effects of treatment. The importance of physical exercise is often underestimated in Oncology, above all because of the need for an individualized approach and for a lack of recommendations that are valid for everyone. The literature now states that rehabilitation and exercise are as important as medical care. The National Cancer Institute in Aviano (Italy) has started a rehabilitation program for patients treated for breast cancer, followed by an assisted path to encourage physical activity. Thanks to various co-production processes, this program allows women to benefit from a personalised plan and it will be possible to assist patients and encourage physical activity through use of a mobile app. A synergy between the health and fitness worlds has been created, through co-production, accustoming patients to exercise during and following treatments.