Higher HRV is associated with more positive emotion states, as well as better emotion regulation. Higher HRV indicates your nervous system is responding dynamically to the environment. In other words, your body stays in “rest and digest” mode when the situation doesn’t require you to be on high alert, but when you’re in a stressful situation, your body adjusts to go into “flight or fight” mode. This balance between your parasympathetic and sympathetic nervous system is healthy. Lower HRV means that your body is not dynamically adjusting in this way, and more likely to stay in “flight or fight” mode even when it’s not helpful.