This is how well the autonomic nervous system is regulating the body’s physiology. It tells us if there is a balance or imbalance between the sympathetic nervous system (our gas pedal) and the parasympathetic nervous system (the brakes).  If a person is locked in sympathetic dominant mode the body is in a state of hypervigilence  or fight or flight. When this happens we know that the heart rate goes up, BP goes up, and digestive functions are shut down as well as the body’s ability to detoxify. In dominant sympathetic mode, powerful hormones such as cortisol are damaging neurons in the brain not to mention the immune system suffers as well.