Comparison of the Acute Effects of Auricular Vagus Nerve Stimulation and Deep Breathing Exercise on the Autonomic Nervous System Activity and Biomechanical Properties of the Muscle in Healthy People

Background/Objectives: We aimed to examine the acute effects of deep breathing exercise and transcutaenous auricular vagus nerve stimulation (taVNS) on autonomic nervous system activation and the characteristics of certain muscle groups and to compare these two methods. Methods: 60 healthy adults between the ages of 18-45 were randomly divided into two groups to receive a single session of taVNS and deep breathing exercises. Acute measurements of pulse, blood pressure, perceived stress scale, autonomic activity and muscle properties were performed before and after the application. Results: A significant decrease was detected in the findings regarding the perceived stress scale, pulse and blood pressure values as a result of a single session application in both groups (p <0.05). In addition, it was determined that the findings regarding autonomic measurement values increased in favor of the parasympathetic nervous system in both groups (p <0.05). In measurements of the structural properties of the muscle, the stiffness values of the muscles examined in both groups decreased (p <0.05), while the findings regarding relaxation increased (p <0.05). As a result of the comparative statistical evaluation between the groups, the increase in parasympathetic activity was found to be greater in the deep breathing group (DB) (p <0.05). In the measurements made with the Myoton®PRO device, a significantly higher decrease in the stiffness value of the erector spinae was detected in the respiratory group (p <0.05). and an increase in the relaxation values was detected in the erector spinae and gastrocnemius muscles (p <0.05). Conclusion: It has been observed that both methods can increase parasympathetic activity and muscle relaxation in healthy people in a single session. However, DB seems slightly superior to taVNS in this respect.