Heart Rate Variability; Insight into the Nervous System.
Heart Rate Variability (HRV) is an exciting technology for evaluating autonomic nervous system balance and activity. HRV enables Doctors of Chiropractic to objectively evaluate how effectively the nervous system is regulating the activity of a vital organ.

There is a two way communication system between the brain and the heart. Analysis of the beat to beat patterns of the heart may be used to evaluate balance between the sympathetic and parasympathetic divisions of the autonomic nervous system. When the two branches of the autonomic nervous system are working together at a maximum efficiency, you feel "in sync." This is because the sympathetic and parasympathetic divisions are not fighting one another. This state of being is called "entrainment."

Variability in heart rate reflects the vagal and sympathetic function of the autonomic nervous system, and has been used as a monitoring tool in clinical conditions, characterised by altered autonomic nervous system function. Spectral analysis of beat to beat variability is a simple, non invasive technique to evaluate autonomic dysfunction.