Constantin: monitor effort drift against your session average
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@Speed-Man thanks for your review! Noted. I’ve reduced the app to one screen because of stability issues but since I’ve found a new, stable method - perhaps it’ll be possible to get back to different screens too and the visible delta.
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@Speed-Man you can go to watch settings in the Suunto App, then view the apps that are synced to the watch, select Constantin and scroll to the bottom of the page to see when it was updated.
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@Łukasz-Szmigiel Now it’s on the latest version. Thank you very much for the support and continuous improvements
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Constantin 2.12
Steadier drift view, new detail screens, and a website
Hi everyone,
I’ve just published Constantin 2.12, a new version of my SuuntoPlus app for monitoring movement-speed and heart-rate drift during workouts.
What’s new in 2.12
This release focuses on making the app clearer, smoother, and more stable during real workouts.
Three switchable views
Three views are back, but this time without the need of reloading the template:
- Drift — combined movement-speed and heart-rate trend
- Pace / Speed / NGP — movement-speed detail view
- Heart Rate — HR detail view
The upper button switches between them:
- short press: next view
- long press: previous view
All views share the same collected trend data, so switching views does not reset the chart.
Smoother and more representative trend chart
Trend values are now averaged over each recording interval during up to 10 minutes (four bucket, each 2:30 min average + “now” refreshed every 3 seconds). The chart now reaches further back and gives a broader view of how effort is changing over time.
Better behavior when data briefly drops
If GPS/speed data drops briefly, the chart should hold its history instead of clearing. When you stop moving without pausing the activity, the movement-speed trend holds the last valid sample while heart rate can continue updating.
Shared scale for pace and heart rate drift
In the combined drift view, both lines now share one visual scale and meet at the same point on the right. This should make it easier to see whether movement speed and heart rate are drifting together or diverging.
HR zone bar appears immediately
The heart-rate zone bar now appears as soon as an HR zone is active, without waiting for the trend chart to fill.
More stable alongside navigation and other SuuntoPlus apps
A lot of work in this release went into making the app behave more calmly under load, especially when used together with route navigation or other SuuntoPlus apps.
Website with details
I also published a small website with more details, screenshots, and explanation of how the app works:
https://constantin.szmigiel.design/
Feedback is very welcome, especially from people testing it during longer workouts, route navigation, or together with other SuuntoPlus apps.
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Thank you so much. You did an amazing job designing everything—it all looks great.
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2.13 (2026-06-27) is live with a small bugfix:
- Each trend line now scales to its own movement, so a chart looks the same whether you view it in the combined drift view or in its own dedicated view.
- Fixed the effort direction for speed-based sports (such as hiking): moving faster than your average now correctly reads AHEAD instead of FADE (and correct green/red colors).
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Hi guys!
I’ve received a report from Suunto App from someone using Suunto Race S saying that Constantin is still crashing and rebooting the watch when used with manual laps without any other apps or GPS routes loaded.
I’m unable to reproduce such behaviour on my S9PP. Can somebody with Race S see if the app triggers the crash with manual laps triggered?
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2.14 (2026-07-07)
- The heart-rate zone bar and trend chart now react right away in workouts without speed data — indoor sessions, or while waiting for a GPS fix — where they could previously lag behind by a couple of minutes.
- The view you selected stays selected after lap and other watch overlays, and the trend keeps averaging smoothly through them.
- Shows – instead of STABLE until there is enough data to judge your effort.
Also, I’ve spammed 30+ manual laps and cycled through screens like mad and all is stable as a rock. Just didn’t manage to breake the app or the watch.
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I don’t know if others are experiencing the same issue on R2, but I can’t use this application. It seems like it’s not working at all.
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@Speed-Man can you explain a little bit more? What are you experiencing?
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@Łukasz-Szmigiel This morning I went for a run, but the Constantin app didn’t display my heart rate or speed on the screen. I checked it again just now, and it seems to be working normally now.
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