Heart Rate Measurement Failed

How to Fix It

1. Tighten the band.

   The sensor needs firm contact with skin.
   Tighten so the watch does not slide on the wrist but is not painful.
   One finger-width above the wrist bone is the standard position.

2. Clean the sensor area.

   Wipe the back of the watch with a soft cloth and water.
   Sweat, lotion, and sunscreen build up over weeks of wear.
   Dry thoroughly before placing the watch back on the wrist.

3. Stay still during the reading.

   Sit or stand quietly for 10 seconds while the sensor reads.
   Movement during the measurement causes failure.
   The watch shows a heart icon while reading — wait until it shows a number.

4. Warm up cold hands.

   Cold skin reduces blood flow at the wrist, weakening the optical signal.
   Rub your hands together or step indoors for a minute before retrying.
   Resolves a meaningful share of measurement failures in winter.

5. Check sensor obscuration.

   Look at the back of the watch.
   The sensor cluster has 2-4 visible LEDs and photodiodes.
   If any are scratched, scuffed, or covered by stickers, the reading fails.
   Light scratches are normal; deep gouges may need warranty repair.

6. Restart the watch.

   Hold the side button → Restart.
   Sometimes the sensor calibration gets stuck and a reboot refreshes it.
   After restart, retry the heart rate measurement.

7. Tattoo workaround.

   Heavy dark tattoos directly under the sensor block the optical signal.
   Try wearing on the other wrist or higher up the arm.
   Samsung acknowledges this hardware limitation.