Heart Rate Measurement Precautions

The following points should be noted in order to measure heart rate properly.

Heart Rate Measurement Functions

• The back cover of the watch has a built-in sensor that detects your pulse. This is used to calculate and display an approximate heart rate value. The factors below can cause error in the displayed heart rate value.
  - How the watch is affixed to the wrist
  - Individual wrist characteristics and condition
  - Training type and/or intensity
  - Sweat, dirt, and/or other foreign matter around the sensor
  All of this means that heart rate values displayed by the watch are approximate, and no guarantees are made concerning their accuracy.
• The heart rate measurement function of this watch is intended for recreational purpose, and should not be used in any way for medical purpose.

Movements that affect heart rate measurement

• Activities or specific movements * in which you move your arm only violently may affect the heart rate measurement and cause an error in the heart rate data displayed by this unit.
  *Movement that moves the wrist violently or movement that twists the wrist (eg, playing percussion instruments, tennis, etc.)

Warm-up before training

• Due to cold conditions and cold hands, weak blood circulation may affect heart rate measurement.
• Before training with heart rate measurement, please perform proper warm-up in advance.

Precautions When Putting on the Watch

Correctly wearing the watch on your wrist is essential obtain more accurate heart rate measurements. Position the watch on your wrist as described below.

1. With the watch fastened loosely on your wrist, place at least one finger to the right of the pressure sensor on the right side of the watch * (Figure 1).
   *If you wear the watch on your right wrist, place your finger(s) to the left side of the watch.
   

   

   • If the watch covers the protruding bone of your wrist (your ulna, which is circled in the nearby figure 2), keep adding fingers until it doesn’t anymore.
     

     

   • The location and shape of this bone differ from person to person.
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 3)
   

   

3. After you determine the best wrist position for the watch, tighten the wristband securely enough to keep the watch from sliding on your wrist.
   
   • Make sure the sensor and arm are in close contact so that the light from the sensor does not leak out.
   • Do not overtighten the wristband.