High HVR is generally considered an indicator of a healthy heart.ĮCG (Electrocardiogram) App: Place your thumb and forefinger on opposite corners of the Sense’s screen to perform a 30-second ECG and generate a report to share with your doctor. Tracking HRV can clue you into your body’s signs of stress, illness, and fatigue. Heart Rate Variability (HRV) monitoring: HRV is the variation in the amount of time between each heartbeat, measured in milliseconds. Bookmark this page and refer to this as you need to decide which are most important for you to have in your tracker. We’ve broken down several features and terms you’re likely to see while shopping for a tracker, from the most common and straightforward functionalities to the lesser-known and sometimes confusing alphabet-soup acronyms. Some functions are more premium, reserved for higher-end models like the Sense, while others are fairly standard across nearly every device the brand offers. Not every Fitbit offers all of the features listed below. $60 at Amazon $80 at Walmart $80 at Fitbit Feature Cheat Sheet