There are 2 branches of the vagus nerve. In an overly broad stroke, one bundle is wired to a body's upper half and the other bundle the lower half.

Many simple moves, such as eyeball rolls and head rolls activates the upper. Many simple moves found in Brain Gym ( a workbook for gradeschool teachers to guide their classroom through sensory integration (SI) movements) address both lower and upper.

There is also much value in looking into Donna Eden's work. One can see much qigong and acupuncture insights in her book, Energy Medicine (1998), but there are much more and it is presented in a way that empowers self-care.