Background Cardiac autonomic neuropathy (CAN) is one of the most ignored complications of type 2 diabetes mellitus (T2DM). One of the indicators of CAN is a low heart rate variability (HRV). Rate-pressure product (RPP) indicates myocardial oxygen consumption. Theoretically, a reduction in HRV (due to increased resting HR (> 100 bpm) in T2DM) will lead to an increase in the resting RPP and, thereby, myocardial blood flow and oxygen consumption. However, no numerical relationship has been established.