Heart rate variability (HRV) as a measurement of autonomic function assumes great clinical importance. It is well known that particular patterns of body fat distribution increase coronary heart disease risk both in adults & children. While frank obesity is associated with reduced HRV, indicative of poorer autonomic nervous system (ANS) function, the association between body mass index (BMI) and HRV is less clear. The dynamic autonomic responses during exercise can be measured to give actionable information for training by analysis of the ECG to determine heart rate variability. While application of HRV has been applied to predict sudden cardiac death and diabetic neuropathy in assessing disease progression. The study revealed the changes in HRV in resting condition and also after a single bout of sub maximal treadmill exercise (50% of VO2 max.)