Nonlinear, Multicomponent Physical Exercise With Heart Rate Variability-Guided Prescription in Women With Breast Cancer During Treatment: Feasibility and Preliminary Results (ATOPE Study) González Santos, Ángela López Garzón, María de la Cabeza Gil Gutiérrez, María del Rocío Salinas Asensio, María del Mar Postigo Martín, Elisa Paula Cantarero Villanueva, Irene Breast Neoplasms Exercise Therapy Mobile Applications Quality of Life The study is funded by the Fondo de Investigación Sanitaria del Instituto de Salud Carlos III and the Fondos Estructurales de la Unión Europea (FEDER) (PI18/01840). Á.G.S. has received funding for its training with the grant FPU18/03575 by the Spanish Ministry of Education Cultura y Deporte. M.L.G. has received funding for its training with the grant FI19/00230 by the Fondo de Investigación Sanitaria del Instituto de Salud Carlos III. R.G.G. has received funding for its training with the grant FPU20/05674 by the Spanish Ministry of Education Cultura y Deporte. Additional funding is provided by the European Regional Development Fund (ERDF, SOMM17/6107/UGR), “Plan Propio de Investigación 2021” University of Granada (PPJIB2021–13) and the Spanish Ministry of Economy and Competitiveness (Plan Estatal de I + D + I 2013–2016). Objective. The purpose of this study was to examine the feasibility, safety, adherence, and preliminary efficacy of the ATOPE program during radiotherapy (RT) or chemotherapy (CT) for women with breast cancer. Methods. This single-blind, pretest–posttest feasibility study included 38 women with breast cancer at the beginning of their treatment. The ATOPE program consisted of 12 to 18 sessions of a multimodal physical exercise program, prescribed based on daily heart rate variability and clinimetric assessments using the ATOPE+ mHealth system. Overall health was assessed with quality of life, autonomous balance, and body composition, whereas health-related fitness was measured through functional capacity, physical activity levels, and upper and lower limb strength. Results. The rates of recruitment, retention, and adherence were 52.35, 73.68, and 84.37%, respectively, and the satisfaction rating was 9.2 out of a possible 10 points. The perceived health status change score was 3.83 points, scored on a −5 to 5 point scale. No adverse effects were found. Compliance results showed that the ATOPE+ mHealth system was used on 73.38% of the days, and the Fitbit bracelet (Google, Mountain View, CA, USA) was used on 84.91% of the days. Women stayed physically active 55% of days. Regarding preliminary results, for overall health, the percentage of body fat in the RT group decreased by 1.93%, whereas it increased by 5.03% in the CT group. Lower limb strength increased in the RT group, specifically knee extensor isometric strength (6.07%), isokinetic knee flexors 180 degree/second (1.53%), and isokinetic knee extensors 300 degree/second (4.53%), in contrast with the reductions found in the CT group (11.07, 18.67, and 14.89%, respectively). Conclusion. The ATOPE program, through nonlinear prescription based on daily monitoring with the ATOPE+ mHealth system, is feasible and safe for application during breast cancer treatment. The results suggest that the overall health can be maintained or even improved regarding most variables. Impact. This study focused on the feasibility, safety, and completion of a physical therapist-led program at early diagnosis for adults with breast cancer. The multimodal, supervised, tailored, nonlinear physical exercise program is feasible and safe, showed a good completion rate, and was able to prevent the quality-of-life deficits that are often triggered by systemic breast cancer treatment. This study highlights the importance of daily morning assessments using the ATOPE+ mHealth system in patients with breast cancer to prescribe nonlinear physical exercise. 2023-12-18T13:23:22Z 2023-12-18T13:23:22Z 2023-06-22 journal article González Santos, Á. et al. Nonlinear, Multicomponent Physical Exercise With Heart Rate Variability-Guided Prescription in Women With Breast Cancer During Treatment: Feasibility and Preliminary Results (ATOPE Study). Physical Therapy, 2023; 103: 1–11. [https://doi.org/10.1093/ptj/pzad070] https://hdl.handle.net/10481/86322 10.1093/ptj/pzad070 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional Oxford University Press