Vertical 2 Optical HR Sensor Shuts Down Too Easily: Request for Greater Tolerance via Firmware Update
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I’m opening this post anyway because I think this is not an isolated issue and it could probably be solved with a software change.
I can’t use my Vertical 2 24/7 due to the optical sensor issues already reported in other posts, and this really disappoints me.
Wearing it on my right wrist, as suggested, is not a solution: I don’t wear watches on my right wrist and I don’t want to start.
After doing some research, I read that the Suunto sensor has very low tolerance for SNR (Signal-to-Noise Ratio).
This is great for achieving accurate wrist-based heart rate readings, but it causes the sensor to shut down if skin conditions are not perfect.
This policy might make sense if the wrist OHR sensor were also used for training, but it isn’t, because accurate HR measurements require a chest strap (without a chest strap it’s not even possible to use ZoneSense).
So, in an attempt to improve wrist HR accuracy, wrist HR measurement becomes practically unusable.
Given the recent firmware updates, it’s clear that Suunto takes inspiration from what users write on the forum, so I’ll try to contribute as well.
In everyday and night use, the watch moves, gets bumped, shifts position, and can be worn tighter or looser.
A bit more error tolerance is necessary so that the sensor doesn’t turn off due to minor reading issues and remain off until the user notices it’s no longer working.
When the sensor is on, heart rate detection is accurate.
Moreover, with the Vertical 1 (which used a different type of sensor), I never had this problem.
I hope for a small change that will allow me to use the Vertical 2 every day in normal daily life.
Best regards.
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@Manuel-Extreme just a small advice for the watch staying more stabil on the wrist: As much as I love that Power Orange strap myself, get yourself one of the textile Athletic 7 straps. More comfy, and the watch stays just where it is…
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@2b2bff The problem is that, if it stays where it is, it remains on the tattoo and the HR sensor turns off after a while.
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What I’m asking for is not lower accuracy during activities, but a different operating logic between activity mode and 24/7 tracking.
During activities:
- Keep the current strict SNR threshold.
- Prioritize signal quality and accuracy.
- If conditions are sub-optimal, the user can rely on a chest strap anyway.
During 24/7 and night tracking:
- Use a more conservative and tolerant algorithm.
- Accept a slightly noisier signal instead of shutting the sensor down.
- Apply stronger temporal smoothing and trend-based validation rather than instant SNR rejection.
- Never fully disable the sensor unless there is a true hardware failure.
From a user perspective, this would solve the real problem:
- In daily life the watch inevitably moves, rotates, and loosens.
- Micro-motion, skin compression, sweat, temperature changes and external contacts are normal.
- A minimal tattoo, as shown in the photo, is irrelevant from a physiological point of view and should not trigger a sensor shutdown.
Right now the behavior is binary:
- Good conditions → excellent HR detection.
- Slightly imperfect conditions → sensor off, sometimes for hours.
This is not acceptable for a device that is marketed with:
- 24/7 HR
- Sleep tracking
- Recovery metrics
- Stress and resources monitoring
A more fault-tolerant logic would:
- Preserve all activity tracking features.
- Restore reliability of h24 metrics.
- Reduce user frustration and false “no data” periods.
- Align the device behavior with real-world usage.
From a technical standpoint, this looks like a software policy choice, not a hardware limitation.
Other manufacturers already differentiate thresholds and filters between:
- Workout HR
- Background HR
- Sleep HR
I’m confident Suunto can do the same.
I’m not asking for perfection.
I’m asking for continuity instead of shutdown.Best regards.
