Summary Background The aim of the study was to evaluate correlation of breath holding index (BHI) as functional parameter for intracranial subclinical atherosclerotic changes – we have shown in our previous works and arterial stiffness (AS – functional parameter for extracranial subclinical atherosclerotic changes) in diabetic patients with well and poor controlled glucose blood values in correlation with healthy population. Patients and methods We included 60 volunteers divided into 3 aged standardized groups – healthy volunteers, patients with well controlled diabetes and patients with poor controlled diabetes. We excluded individuals with moderate and severe carotid stenosis. Results There was decreasing trend in BHI values and increasing trend in AS values in diabetic patients, especially with poor regulated blood glucose values (r=−0.14 and 1.42; p<0.05). Conclusion These results show that decline in BHI as parameter for intracranial microvessel dysfunction is in good correlation with increase of AS as functional parameter of extracranial vascular aging in diabetic patients.