There are a few reasons why your Garmin might not be taking your heart rate. Make sure the wrist heart rate sensor is enabled, the watch is worn snugly, the sensor area is clean, and you are wearing the watch correctly. Try restarting your watch or using a chest strap heart rate monitor
In this study, the Polar H7 chest-strapped heart rate monitor was used as the criterion measure in 2 fitness trackers, namely Xiaomi Mi Band 2 and Garmin Vivosmart HR+. The real-time, second-by-second heart rate data obtained from both devices were recorded using the broadcast heart rate mode. Avoid scratching the heart rate sensor on the back of the device. Wear the device above your wrist bone. The device should be snug but comfortable. Wait until the icon is solid before starting your activity. Warm up for 5 to 10 minutes and get a heart rate reading before starting your activity. NOTE: In cold environments, warm up indoors. The Best Chest Strap: POLAR H10 Heart Rate Monitor Chest Strap. 4. The Best Battery Life: Wahoo Fitness TICKR FIT Heart Rate Monitor Armband. 5. The Best Smartwatch With ANT+: Garmin fēnix 5 NDYWlG2. 97 303 961 933 37 328 711 149