Comparison of Breathing Exercises and Auricular Vagus Nerve Stimulation Effects on Autonomic Nervous System Activity and Respiratory Functions in Healthy Adults: An Active Comparative Controlled Study

Introduction Vagal modulation is achieved directly by transcutaneous auricular vagus nerve stimulation, whereas breathing exercises stimulate arterial baroreceptors. In this study, we aimed to compare these two methods, which have similar effects. Methods 88 healthy participants aged 18–35 were randomly divided into breathing exercises (Group BE) and vagus stimulation (Group VNS). Thoracic expansion exercise was performed in the BE group. In the VNS group, biphasic electrical stimulation was applied to both ears with a pulse width of 300 ms, a frequency of 10 Hz, and 20 min. Pulmonary function tests were measured on the first and last days. Heart rate, systolic and diastolic blood pressure, RMSSD, PNN50, LF/HF, LF Power, and HF Power values were measured before and after each of the 10 sessions for both groups. Results Heart rate decreased significantly in both groups, with significant superiority in the BE group compared to that in the VNS group. In both groups, blood pressure values decreased significantly. RMSSD, PNN50, and HF values increased significantly in the VNS group, while LF and LF/HF values decreased significantly in the BE group. In pulmonary function test results, the FEV1 value increased significantly in both groups. A significant increase in the FVC value was observed in both groups, but the BE group was superior. The two groups had no significant superiority in the FEV1/FVC value. Conclusion As a result, auricular vagus stimulation seems superior to breathing exercises in increasing the parasympathetic system activity, reducing sympathetic activity, and partially increasing respiratory functions. Clinical Trial Registration NCT06531954