Heart Rate Variability Biofeedback (HRVB) empowers clients to improve their emotional self-regulation. HRVB professionals regularly use quantitative and graphic methods of analysis of heart rate to help their clients understand their own physiological status and the relationship between autonomic function and well-being. This didactic presentation will use actual pre-post HRVB data from patients with PTSD and pain to illustrate how acquisition of the skill of self-regulation through HRVB affects heart rate patterns and screen displays. Coherence is the term used currently to refer to the 0.1 Hz HRV peak, which is indicative of optimum HRV that results from synchronization of cardiac vagal afference and baroreflex. HRV clinical applications and research focus on Coherence as an index of adaptability. Methods of quantifying Coherence from a typical HR tachygram will be explained.