My Garmin Fenix 8 Heart Rate Sensor Is Inaccurate

I purchased a Garmin Fenix 8 smartwatch online from Uzman Teknoloji, with Baytekin Garmin serving as the official distributor in Turkey. I received the item on the 13th, but I was forced to send it in for warranty service immediately after delivery. Subsequently, another unit was shipped to me on the 19th.

However, with this second watch delivered on the 19th, I noticed that the heart rate sensor fails to measure accurately. On March 22, while cycling, I felt extremely fatigued, yet the Garmin Fenix 8 unexpectedly displayed a low heart rate reading. To test the watch, I simultaneously wore a Samsung Galaxy Watch Ultra on my wrist. During this simultaneous test, the Watch Ultra recorded my heart rate between 130–140 bpm, while the Garmin Fenix 8 consistently measured around 110–120 bpm, revealing a significant discrepancy. In colder weather, this inconsistency becomes even more pronounced, making the device unreliable.

Garmin's official website states that the wrist must be clean, the sensor must maintain firm contact, and movement should be controlled. Despite adhering strictly to all of these guidelines, the issue persists. Under identical conditions, my Samsung Galaxy Watch Ultra, Galaxy Watch 7, and other watches yield no such problems; this deviation occurs exclusively with the Garmin Fenix 8. Therefore, the issue lies not with my usage, but directly within this device's heart rate sensor.

I have heard rumors that registering devices on Garmin Connect causes complications during warranty claims, so I also reached out via email, but I have received no response to date. Considering the price paid for this level of device, I expect accurate tracking of essential health data like heart rate. Furthermore, discovering that similar complaints regarding this model's heart rate sensor are widespread online—particularly on international forums—makes this situation completely unacceptable.

Because the device fails to deliver accurate and reliable data, I demand a full return of my Garmin Fenix 8 smartwatch and a complete refund of my purchase price. Due to this experience, I strongly advise against purchasing the Garmin Fenix 8, and I encourage anyone considering this watch to avoid it so they do not face the same disappointment.