Direct answer
Optical heart-rate spikes can come from loose fit, cadence lock, cold skin, tattoos/hair, motion or sensor contamination. Compare a chest strap or manual pulse when safe.
What this covers
- The observed symptom matches this record
- Customer-accessible settings, connections and external components
- Diagnosis before reset, deletion or component replacement
What it does not cover
- ×A model-specific error code with a different documented meaning
- ×Internal electrical, battery-cell, gas, refrigeration or sealed-component repair
- ×A guarantee that every model exposes the same control label
Capture the exact symptom
ReversibleNote activity, cadence, temperature, fit and whether the spike is physiologically plausible.
Run the smallest isolation test
ReversibleClean the sensor, wear it snug above the wrist bone and warm up; pair a compatible chest strap for comparison.
Correct only the proven cause
ReversibleUse the sensor that remains reliable for the activity and update device firmware.
Verify before changing anything else
ReversibleRepeat a moderate controlled workout and compare optical and reference readings.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Exact questions
Common follow-ups
What should I check before resetting anything?+
Note activity, cadence, temperature, fit and whether the spike is physiologically plausible.
What is the safest isolation test?+
Clean the sensor, wear it snug above the wrist bone and warm up; pair a compatible chest strap for comparison.
When should I stop troubleshooting?+
Stop exercise and seek medical care for symptoms such as chest pain, fainting or severe shortness of breath regardless of device data.
Answer for the exact device and software version shown above.