Heart Rate Variability (HRV)  is an important measure of autonomic nervous system (Read more about Stress and ANS here) and there is increasing research in the area of HRV and its positive benefits in metabolic disorders (e.g. diabetes, hypertension) and general wellness. HRV is the physiological phenomenon of variation in the time interval between heartbeats. It is measured by the variation in the beat-to-beat interval. HRV is used to identify potential health challenges by medical doctors. HRV can also be used as a marker of stress (or autonomic nervous system imbalance).  In general, higher HRV (more variations in the interval) indicates a more balanced