TSS (hr) different for imported activities

Matěj Novotný

short version:
I love TSS charts and Suunto App. TSS (hr) is way lower for activities recorded by Race S compared to activities imported from either Garmin or Polar. Can I do something about that?

long version:
I am Suunto fan for long time, I still own working ~10 years-old Ambit 3 sport watches. I am doing different sports (rock climbing, skitouring, running, hiking, etc.) and I like to use TSS charts to track my overal activity load. I like Suunto App for these TSS charts, for it’s great UI/UX, I use it as my activity diary including photos for my activities, I have there my old activities imported from Movescount. I wanted some better watches few years ago, mainly “aerobic GPS” activities. Suunto 9 Peak pro was the best offering from Suunto of that time so I ended with Garmin Fenix 7s. Watches are ugly but works well, Garmin Connect is horrible, doesn’t show TSS charts and doesn’t work offline. I have found iPhone app called RunGap which can read activities from Garmin and write them to Suunto. Some time later, I started measuring HR also for my rock climbing, I ended using Polar Verity Sense and it’s memory for it’s convenience. I also use RunGap to sync from Polar to Suunto. Recently I started playing with Suunto Race S as I would like to get rid of my ugly Garmins. I also had to mention that I use chest strap for aerobic activities, not unreliable optical HR, I like idea of ZoneSense. Optical is fine for rock climbing for me.

So my current setup is:

Garmin Fenix 7s (aerobic activities) -> Garmin Connect -> RunGap -> Suunto App
Polar Verity Sense (rock climbing) -> Polar Flow -> RunGap -> Suunto App
Suunto Race S (testing for aerobic) -> Suunto App

The issue which I have is that I will get 2x smaller TSS (hr) for same activity measured by Race S (or Ambit 3) compared to same activity measured by Fenix 7 or Verity Sense and imported. That is making my TSS charts completely useless. I have same maxHR and almost same HR zones on both watches. I can get rid of Garmin and switch to Suunto for my aerobic activities, but I would be difficult to avoid Polar as it is very inconvenient to use watches while climbing. And even if I will be able to switch completely to Sunnto, I will have huge jump in my TSS charts which I don’t like.
Is there some solution? Maybe TrainingPeaks, but the membership is expensive, and I don’t know if I would like their iphone app.

Mff73

@Matěj-Novotný
short answer : for imported activities, TSS is following “default” HR zones, and not user (per suunto watch) own zones -> thus TSS is different.
You can’t do anything else voting for some posts in this forum to ask Suunto manage such topic. ‍️

Matěj Novotný

@Mff73
Do you mean default which is similar for all users? Because, I have my max HR and resting HR set to same values both in the app and on watches.
Do you know where I can vote for such fix?

Likarnik

@Matěj-Novotný yeah, I have same issue, I set TSS manualy

Matěj Novotný

@Likarnik But how to calculate or estimate it? Do you use some coefficient which you calculated by comparing different measurements of same activity?
I can imagine doing that because my rock climbing sessions especially in gym had vary similar HR pattern and only difference is that when I climb overhangs I have higher peaks compared to climbing slabs. So coefficient * TSS should give good enough results. I can record few sessions with both Polar and Suunto to calculate the coefficient.

Likarnik

@Matěj-Novotný I sync all my data to intervals.icu as it is better tool for analysing activites, loging gear usage, seting zones and so on. So I import activity to SA, which is then synced to intervals.icu where TSS (Load) is calculated and then I set maunal TSS back in SA.

sunter

Hi everyone,
I contacted Suunto Support regarding an issue with Heart Rate zone distribution and TSS calculations for activities synced from my Hammerhead Karoo unit.
Currently, third-party imported activities ignore custom HR zones set on the watch and instead rely on Suunto’s default backend algorithms. As a result, rides synced from my Karoo end up with mismatched HR zones (e.g., shifting Zone 2 efforts into Zone 1), which directly distorts HR-TSS, CTL, and ATL tracking in the Suunto App.

I strongly request that Suunto allows manual HR zone configuration directly within the Suunto App (or enables synced activities to respect the watch’s custom HR zone settings/LTHR). This would ensure that data imported from head units like Hammerhead is categorized accurately.

Below is the official response I received from Suunto Support confirming this current limitation:

Thank you for contacting Suunto Support and for providing the detailed information.

We understand that you are recording cycling activities with your Hammerhead Karoo 3, which are then automatically synced to the Suunto App, and that you have noticed differences in the heart rate zone distribution between the Hammerhead platform and the Suunto App.

Regarding imported activities from third-party platforms, the heart rate zone analysis displayed in the Suunto App is calculated based on the settings and algorithms used by Suunto. The HR zones configured on your Suunto Race S watch may not be applied to activities imported from other services, which can result in differences between the original platform and the Suunto App.

At the moment, the Suunto App does not support setting independent heart rate zones specifically for imported third-party activities. Therefore, there is currently no setting available to force imported activities to use the HR zone configuration from Hammerhead.

We appreciate your feedback regarding this functionality. We will forward your comments to the relevant team as user feedback for future improvements.

Thank you again for your understanding and support.

Kind regards,
Suunto Support Team