Stress-Reducing Intervention in Patients With Colorectal and Breast Cancer

This is a prospective, interventional, clinical study with in 2 cohorts. Target of subjects is 50 per cohort and an anticipated total duration of 36 months. Participants will undergo 4 sessions of HRV BI with the trainer where they will learn about the prognostic role of the vagal nerve in cancer and in reducing distress and pain, and how to perform deep paced breathing with the HRV monitoring. They will perform the training daily (3-times, minimum 7 minutes each) at home with the online control for 3 months. Researchers will compare the effect of addition of 3-months training of HRV BI to SOC on inflammation, HRV, quality of life (QoL), cognitive functions, salivary cortisol slopes, sleep quality and treatment outcomes of patients with colorectal and breast cancer.