ABSTRACT
Diabetes mellitus (DM) affects more than 366 million people around the world. One of the serious clinical complications of DM is cardiovascular autonomic neuropathy (CAN), which gradually results in abnormalities of heart rate (HR) control and vascular dynamics. A decrease in heart rate variability (HRV) during deep breathing or exercise may be a sign of autonomic neuropathy and is associated with a high risk of coronary heart disease in patients with or without diabetes. The Valsalva maneuver is performed by having the participant exhale for 15 seconds, while maintaining an expiratory pressure of 40 mmHg. Expiratory pressure can be measured by having the patient blow into a mouthpiece connected to a pressure transducer. Respiratory sinus arrhythmia is assessed by performance of six deep breaths per minute at a frequency of 0.1 Hz. The timed breathing is performed with the aid of a metronome or verbal cues.
