The  Body Battery ™  of  Garmin  analyzes heart rate variability  -  the time interval between each heartbeat - to indicate whether you are having a quiet day, balanced, stressful, or is in any intermediate stage. A high Body Battery value indicates that the user should remain active, a low number suggests rest for recovery. This system helps users assess and create patterns to better understand how their past-day behaviors and activities influence how they feel at a given moment.