Effect of heart rate variability biofeedback training on peripheral sensory status and cardiac autonomic status in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by high blood sugar levels due to insulin resistance when the body cannot fully respond to insulin. Diabetic neuropathy is traditionally considered a common complication of diabetes which can present in the form of distal symmetrical polyneuropathy (DSPN) and cardiac autonomic neuropathy (CAN). Distal symmetrical polyneuropathyaffects up to 50% of adults with long-term diabetes. Quantitative sensory testing (QST) is a non-invasive tool in which standardized testing procedures allow the quantification of somatosensory functions. Very few studies have quantified peripheral neuropathic status in T2DM using QST but all have reported dysfunction in T2DM. The overall prevalence of cardiac autonomic neuropathy among patients with T2DM is approximately 20 - 73%. It is characterized by impairment of the parasympathetic and sympathetic components of the autonomic nervous system. CAN is a significant cause of morbidity and mortality associated with a high risk of cardiac arrhythmias and sudden death. Heart rate variability (HRV) is a simple non-invasive tool commonly employed to evaluate cardiac autonomic status. A high rate of neuropathic complications indicates the need for investigation into new therapeutic modalities. Heart rate variability biofeedback (HRVB) training is a non-invasive tool that has been shown to be an effective adjunct to standard therapy in various disorders. Very few studies have investigated the effects of HRVB in T2DM patients. Furthermore, no information from any randomized controlled trial for the same is available. Therefore, the present randomized controlled trial is planned to study the effect of HRVB training on the peripheral sensory and cardiac autonomic neurological profile in patients of T2DM.