The method I used involved observation of the breath and pulse. If our pulse is faster on the inbreath and slower on the outbreath, this indi-cates good ventral vagal function. The greater the difference, the better the ventral vagal function. I monitored this by putting a finger over an artery in the client’s wrist while at the same time observing the pattern of her breathing. The idea behind this method goes back to studies on the autonomic nervous system from the 1890s, with the discovery of variability in blood pressure described as Traube-Hering-Mayer waves.
