Transcutaneous vagus nerve stimulation and exercise-induced autonomic regulation: a systematic review

This systematic review aims to evaluate the effects of transcutaneous vagus nerve stimulation (tVNS) on autonomic regulation in response to exercise-induced physiological stress in healthy adults and athletes. The review will focus primarily on vagally mediated heart rate variability, spontaneous cardiac baroreflex sensitivity, sympathetic activity and inflammatory markers. Only randomised controlled trials comparing tVNS with sham or control conditions will be included. Methodological quality will be assessed using the PEDro scale and the revised Cochrane Risk-of-Bias tool (RoB 2), and certainty of evidence will be evaluated using the GRADE framework. Given the anticipated clinical and methodological heterogeneity across stimulation parameters, participant characteristics and outcome measures, a structured narrative synthesis will be conducted.