 Rehabilitation of patients with severe acquired brain injury and low state of consciousness is multimodal. Physical stimulation of the cardiovascular system can be exercised through an array of interventions such as mobilization, standing using a tilt-table, bed-biking, robot-assisted walking or other methods. To the authors knowledge, no studies have been published researching the association between physical stimulation and HRV in patients with severe acquired brain injury in the subacute phase. 