mHealth system (ATOPE+) to support exercise prescription in breast cancer survivors: a reliability and validity, cross-sectional observational study (ATOPE study).

Physical exercise is known to be beneficial for breast cancer survivors (BCS). However, avoiding nonfunctional overreaching is crucial in this population, as they are in physiological dysregulation. These factors could decrease their exercise capacity or facilitate nonfunctional overreaching, which can increase their risk of additional morbidities and even all-cause mortality. The focus of this study is to evaluate the reliability and validity of the ATOPE+ mHealth system to estimate autonomic balance and specific wellness parameters associated with BCS' perceived load, thereby informing nonlinear prescriptions in individualized physical exercise programs for BCS.Twenty-two BCS were included in the reliability and validity analysis. Measures were taken for four days, including morning autonomic balance by heart rate variability, self-reported perception of recovery from exercise, sleep satisfaction, emotional distress and fatigue after exertion. Measures were taken utilizing the ATOPE+ mHealth system application. The results of these measures were compared with criterion instruments to assess validity.The reliability results indicated that the intraclass correlation coefficient (ICC) showed an excellent correlation for recovery (0.93; 95% CI 0.85-0.96) and distress (0.94, 95% CI 0.89-0.97) as well as good correlation for the natural logarithm of the mean square root differences of the standard deviation (LnRMSSD) (0.87; 95% CI 0.74-0.94). Sleep satisfaction also showed an excellent correlation with a weighted kappa of 0.83. The validity results showed no significant differences, except for fatigue. ATOPE+ is reliable and valid for remotely assessing autonomic balance, perception of recovery, sleep satisfaction and emotional distress in BCS; however, it is not for fatigue. This highlights that ATOPE+ could be an easy and efficient system used to assess readiness in BCS, and could help to improve their health by supporting the prescription of optimal and safe physical exercise. Trial registration NCT03787966 ClinicalTrials.gov, December 2019 [ATOPE project]. https://clinicaltrials.gov/ct2/show/NCT03787966 .