The Apple Watch has a special way that you can conserve power during a walking or running workout by automatically disabling both its cellular capability (if any) and its heart-rate sensor. This is especially useful for older devices that may no longer have amazing battery capacity, because nothing sucks more than having your Watch die halfway through a long hike. Believe me, I know; I’m still upset about the missed achievements from the day that happened to me. Yes, I’m petty.
Anyhow, to turn this on yourself, open the Watch app on your iPhone, tap the “My Watch” tab, and then scroll down to find the “Workout” preferences.
Touch that section, and you’ll see the toggle for Power Saving Mode.
As you can read in my screenshot above, using this may make your calorie counts less accurate, but I suppose it’s better to have a functional Watch than accurate energy assessments, right? And be sure to check out the other options available here—“Running Auto Pause,” for example, is fantastic for pausing your running workout when you stop moving and starting it again automatically, meaning that you may get more accurate pace calculations when you’re out and about. Neat!