Background: Evaluating the autonomic system is conducting, among others, by comparing the relationships between the two sub-systems that assembler it: the sympathetic and the parasympathetic systems. In normal conditions, there is balance between both systems which reflects in a highly dynamic heart rate and heart rate variability. As part of the brain injury after stroke, the autonomic system is also damaged. The heart rate variability is decreased and the 24-hour circadian rhythm of heart rate changes.