Purpose: Stress tends to cause sympathetic hyperactivity and increase blood cortisol levels. The vagus nerve is a parasympathetic nerve that is involved in relaxing the body. The purpose of this study was to investigate the effects of electrical stimulation of the vagus nerve on stress hormone (cortisol) levels and heart rate variability (HRV) in humans.
Methods: A total of 10 healthy subjects participated in the pilot experiment. All subjects underwent electrical vagus nerve stimulation for 20 minutes in the cymba conchae of the left ear. An electro cardiogram meter was used to measure HRV. Blood samples were collected and analyzed for cortisol levels. The standard deviation of all normal N-N intervals (SDNN), root mean square of successive differences (RMSSD), low frequency, high frequency, and cortisol levels were compared in pre and post mean values after the intervention. Data were analyzed using the Wilcoxon’s signed-rank test.
Results: Coritsol levels were observed to decrease after vagus nerve electrical stimulation. The mean SDNN and RMSSD values were increased after the intervention, but not significantly.
Conclusion: Vagus nerve electrical stimulation has been shown to increase the ability of the parasympathetic nerve to adapt to upward regulation and stress. Vagus nerve electrical stimulation could thus be an effective treatment for modern social psychological stress control.