Even mindfulness meditation can stimulate the vagus nerve: https://www.psychologytoday.com/blog/the-athletes-way/201602/mindfulness-meditation-and-the-vagus-ne

Even mindfulness meditation can stimulate the vagus nerve: https://www.psychologytoday.com/blog/the-athletes-way/201602/mindfulness-meditation-and-the-vagus-nerve-share-many-powers https://www.psychologytoday.com/blog/the-athletes-way/201602... Since psychological factors have a large effect on vagus tone, it's important to do double-blind trials.