How you wear the watch on your wrist affects the accuracy of heart rate monitor values. Position the watch as described below.

1.With the watch fastened loosely on your wrist, place at least one finger to the right of the power button^* (Figure (1)).

• If the watch covers the protruding bone of your wrist (your ulna, which is circled in the nearby figure), keep adding fingers until it doesn’t anymore.

• The location and shape of this bone differ from person to person.

* If you wear the watch on your right wrist, place your finger(s) to the left of the pressure sensor (left side of the watch).

2.Position the watch so there is at least one finger width between it and your wrist joint when you bend your hand back (Figure (2)).

3.After you determine the best wrist position, tighten the band snugly so the watch does not slide on your wrist.

• To improve measurement accuracy, keep your arm still with the touch screen facing upwards for about the first 15 seconds immediately after the start of a heart rate measurement operation (such as when you start an Activity app measurement).