Cardiovascular Autonomic Neuropath(CAN) is a poorly understood chronic complication of Diabetes Mellitus (DM). A single instrument to evaluate CAN is not available yet, because of the complex balance between both sympathetic and parasympathetic drives. Heart Rate Recovery (HRR) is a promising parameter for clinicians to use, which is the difference between the maximal heart rate achieved at the end of the exercise phase and the heart rate at different stages of the recovery. The objective of this study was to characterize parameters obtained from RR trends during the recovery phase of the Exercise ECG. Our preliminary analysis is performed with 23 patients enrolled in the DM group and 6 patients in the control group. It showed that both HRR1 after the first minute of recovery and HRR2 after the second minute of recovery are able to discriminate between groups. These results are encouraging and more trends analysis within a different window period is still needed.