Heart rate signal(HRS) carries information about autonomic nervous systemic function(ANSF).Powerspectral characteristics of HRS taken from 87 patients with diabetes mellitus(DM) were studied. The resultsfound that the prevalence of diabetic AN was about 63%.Comparing data of control group

spectralindex(TFP.PVV.PHV and RVH) values in DM group were significantly different than those in the controlgroup(P<0.05).The results showed it was possible that the damage of cardiac ANSF in DM patients occured andthat the damage of vagal nerves was more severe or/and occured before the sympathetic nerves in DM patientsaccompanied with abnormalities of ANSF

but the damage of sympathovagal activity was more proportional andtile damage of single nerve was usually vagal nerve. As sympathovagal imbalance

ANSF mainly showed therelatively sympathetic hyperactivity.Hence

using power spectral analysis can provide some information for earlyprevention

diagnosis and treatment of AN.