A new study has found that (tVNS) can improve autonmic function in older adults.

Effects of transcutaneous vagus nerve stimulation in individuals aged 55 years or above: potential benefits of daily stimulation
https://pubmed.ncbi.nlm.nih.gov/31358702/

Autonomic function, which is the regulation of involuntary bodily functions such as heart rate and blood pressure, tends to decline with age. The study found that a single session of tVNS, as well as daily tVNS administered over two weeks, was associated with increased measures of vagal tone and baroreflex sensitivity.

tVNS involves the use of modified surface electrodes placed on the tragus (the small bump in front of the ear) and connected to a transcutaneous electrical nerve stimulation (TENS) machine. The stimulation activates the vagus nerve, which plays a crucial role in the regulation of autonomic function.

The study included three separate experiments. In the first experiment, 14 participants received a single session of tVNS and a sham treatment. In the second experiment, all 51 participants underwent a single session of tVNS. In the third experiment, 29 participants received daily tVNS for two weeks, and their quality of life, mood, and sleep were assessed.

The results showed that tVNS was effective in promoting increases in measures of vagal tone and baroreflex sensitivity, and that the effects were more pronounced in participants with higher levels of baseline sympathetic prevalence (i.e. those with a higher proportion of sympathetic nervous system activity). Additionally, daily tVNS for two weeks was associated with improvements in measures of autonomic function, as well as some aspects of quality of life, mood, and sleep.

These findings suggest that tVNS may be a promising intervention for improving autonomic function in older adults, and that it may be possible to identify individuals who are likely to benefit most from the treatment. Further research is needed to confirm and expand upon these findings.