Aims: This preliminary study aimed to compare the effects of transcuta-neous auricular vagus nerve stimulation (taVNS) alone, deep breathing alone, and their combination on cardiovascular and autonomic regulation in healthy adults before future application in patients with hypertension. Alt-hough both interventions have shown individual efficacy, quantitative com-parison of their combined effect with each single intervention remains limited. Methods: Ten healthy adults without cardiovascular, psychiatric, or res-piratory disorders were enrolled. Electrocardiogram, impedance cardiogram, and systolic blood pressure (SBP) were measured to assess cardiovascular and autonomic responses. During the stress period, all participants performed the Stroop test to induce sympathetic activation. The protocol consisted of four sessions with baseline, stress, intervention, and recovery periods, and four conditions were applied in random order: sham stimulation, taVNS alone, deep breathing alone, and combined condition. Interrupted time series analysis with autoregressive integrated moving average modeling was used to assess level and slope changes while accounting for autocorrelation. Results: A significant increase in SBP during the Stroop test was observed in all conditions except deep breathing alone. Most SBP slopes were not sta-tistically significant, except in the stress of the taVNS and the recovery of the combined. In both deep breathing alone and the combined intervention, stress-elevated SBP decreased significantly during intervention. During re-covery, SBP increased by 7.87 mmHg after deep breathing alone and re-turned rapidly to baseline, whereas after the combined it increased by only 2.99 mmHg and recovered more gradually over about 10 min. In the cardiac output (CO), the combined induced an immediate decrease of 0.693 L/min during recovery, with no significant slope change until the end. Conclusion: These findings suggest that the combined intervention may induce stronger hemodynamic and residual effects than either single inter-vention alone. This preliminary study supports further investigation of the combined intervention in patients with hypertension.