Heart rate variability and insomnia in depressed patients with breast cancer

Depression is associated with unhealthy autonomic regulation. However, whether patients with breast cancer (BC) with different degrees of depression can be identified from linear and non-linear dynamics in the autonomic nervous system is unclear. We aimed to evaluate the differences in linear and non-linear heart rate variability (HRV) parameters in patients with BC with different degrees of depression and the relationship between HRV parameters and depression and sleep disorders.