Garmin Fenix series; Battery life. You can also find features like stress monitoring, guided breathing exercises, women’s health tracking and Garmin’s Body Battery monitor. This looks at Body battery makes it look like I'm dead. Flatliner over 2 years ago. I got the Garmin Fenix 6 pro 2 days ago. Still learning how to read all the stats.. This is my first garmin watch, and first one that does more than heart rate and sleep. I'm incredibly sedentary and shamefully out of shape, but I like gadgets so I got this to motivate myself The Fenix 7 goes up against watches like the Coros Vertix 2 ($699/£599) with its 140-hour GPS battery life, and the Polar Grit X Pro ($429/£379), which is Polar's latest outdoor watch. A Fenix 5x already has stress (All Day Stress & Recovery from FirstBeat), and the same factors that show the stress score are what shows the body battery drain when not active. In other words, if stress is high, body battery will go down even though you're still. Using the Stopwatch. From the watch face, hold MENU. Select Clock > Stopwatch. Select to start the timer. Select LAP to restart the lap timer. The total stopwatch time continues running. Select to stop both timers. Select an option. Clock. Press and hold your Light button for up to 30 seconds until the watch face goes blank, then release the button. Wait a few seconds, then hit the same button again to turn it back on, then charge Fenix 6 Sapphire (without SOLAR) ran out of power on Day 10 while Fenix 6 Pro Solar managed about 12 hours more which corresponds to a battery life extension of about 5%. During the two weeks I went for 8 runs which of course took its toll on the battery. And I think that I was outside for about 2-3 hours a day. The Body Battery metric will estimate the charging or draining during short periods when the device is off. If you do not wear it…. So it used all the data it had, minus the missing overnight, to extrapolate a likely BB value. If you switch the watch off regularly, you will make it less accurate. In theory sound good, i real life, well. OmwZ.