Dr Porges early research career started when the science of psychophysiology was in its infancy. He studied heart rhythms, specifically the time interval between each heartbeat (Heart rate variability) which was recognized as a direct measure of vagal influences on cardiac function. He studied how this time interval varied in different states such as sustained attention or stress and was the first to provide the quantification of such phenomena in 1969.Heart rate variability (HRV) is consider...