Rumors suggest Endurance Score and Activity Impact features could soon launch on Garmin smartwatches. A report by the5krunner, citing @JW as the source, suggests that endurance cyclists, runners or swimmers could use the new tools. The Endurance Score would help you to understand your ability to remain active for an extended time. Two weeks' worth of data will be required to establish your initial score, with the result becoming more accurate as you exercise more.
Data from all completed activities will count towards your Endurance Score, though there will be a weighting in favor of your top three workout types. The endurance algorithm will use tracked activity duration and intensity, speed, power, and VO2 max information, as well as your age, gender, BMI and general activity level. Your Endurance Score will be shown across four weeks alongside suggestions for improving or maintaining the metric. According to the5krunner, Garmin notes that if you typically carry out just one activity, your endurance for other sports may not be improved.
It is unknown precisely what the second Activity Impact feature will measure, perhaps how your recent exercise affects your endurance level. The Training Effect tool can already be used to monitor the impact of a workout on your aerobic and anaerobic fitness. You will be able to view the metrics in Garmin Connect; it has also been suggested that the data could be displayed on Forerunner and Fenix wearables. Presumably, the metrics will also be available on the Enduro, Garmin's endurance smartwatch. The precise launch date of the Garmin Endurance Score and Activity Impact metrics is unknown; the5krunner claims they will be released "imminently".