HeartMath is amazing!
This state-of-the-art technology program shows you your heart beat and respiration in real time, providing you immediate feedback on your current stress levels. Yet, it is so much more than this! By increasing your imagination of breathing through your heart, this researched technique has scientific evidence that each heartbeat is longer and shorter in length, depending upon how stressed we are. This is called, "heart rate variability" or "HRV."
The scientists who created HeartMath learned that if a person learns to control their breathing (imagining it as generating through your heart) this changes these heart beat lengths. The result is a decrease in stress, anxiety and disregulation. However, the best part is that by practicing this over a period of time, a person actually retrains their brain and gains better control over emotions and stress.