Acute effect of vagus nerve stimulation and deep breathing exercise methods on autonomous nervous system and muscle structural features in healthy young adults

Deep breathing exercise methods and auricular vagus nerve stimulation (VNS) have been increasingly used as a noninvasive treatment modality in recent years. In this study, the effects of deep breathing exercise methods and vagus nerve stimulation on vagal modulation and the properties of muscle groups were analyzed and it was aimed to compare these two methods. Healthy adult individuals were divided into two groups, one session of VNS and deep breathing exercises. Pulse, blood pressure, perceived stress scale, e-motion faros and myotonpro measurements performed before and after stimulation, and its acute effects on the structural properties of the autonomic nervous system and various muscle groups were investigated. In both groups, a significant decrease was found in the findings related to the perceived stress scale, pulse and blood pressure values as a result of a single session application. In addition, it was determined that the findings related to the autonomic measurement values in both groups developed in favor of the parasympathetic nervous system. Pulse, blood pressure, perceived stress scale, e-motion faros and myotonpro measurements performed before and after stimulation, and the acute effects of these two interventions on the autonomic nervous system and structural properties of various muscle groups were investigated. In both groups, a significant decrease was found in the findings related to the perceived stress scale, pulse and blood pressure values as a result of a single session application. In addition, it was determined that the findings related to the autonomic measurement values in both groups developed in favor of the parasympathetic nervous system. In the measurements of the structural properties of the muscle, the frequency, stiffness and logarithmic decrease values of the muscles examined in both groups decreased, while the findings related to relaxation increased. As a result of the comparative statistical evaluation between the groups, a statistically significant increase was observed in the respiratory group compared to the other group in the RMSSD, PNN50 and PNS index values, while no significant difference was observed between the two groups in terms of other parameters. Our findings suggested that deep breathing exercise methods and a single session of auricular VNS may increase the values related to the parasympathetic nervous system. In the measurements made with the MyotonPro device, there was a significant decrease in the oscillation frequency and stiffness values between the groups in the m. erector spinae in the breathing group, and in the flexibility values in the m. biceps brachii in the vagus group. In relaxation values, a statistically significant increase was found in the m. erector spinae and m. gastrocnemius values in the breathing group.