Suunto ZoneSense

althaea35

@Brad_Olwin I have been using ZoneSense to help pace my longer aerobic runs quite successfully, but today I did a 3 km assessment effort sandwiched between longish aerobic efforts. I feel that if I used ZS to pace my effort today it could be problematic.

Counter intuitively my ZS reading continued to fall into the ‘green zone’ as the very hard effort of the 3k progressed. Using Runalyze I have determined my HRV data was very ‘clean’ and my subjective feeling aligns to my heart rate.

Any thoughts?

FCDsh

I have noticed that the ZoneSense DDFA index values are displayed in the range 99-101, although the graph here in the screenshots in the forum shows values with “0.x”. Does anyone have any idea why this is the case? I also can’t explain why the training is classified as 100% aerobic, even though I trained in higher heart rate zones? Does the algorithm need to learn more here? alt text

FCDsh

I have noticed that the ZoneSense DDFA index values are displayed in the range 99-101, although the screenshots here in the forum show values with “0.x”. Does anyone have an explanation for this? Also, I can’t explain why the workout is classified as 100% aerobic even though I trained in higher heart rate zones? Does the algorithm need to learn more here?

Screenshot 1

Screenshot 2

dulko79

Not related to your case, but it has been posted in Suunto FB groups there is a bug in ios and the fix is on the way.

Brad_Olwin

@althaea35 Did you have the S+ app running on the watch? Mine today showed VO2M efforts but not on the app.

althaea35

@Brad_Olwin Hi Brad yes it was running on the watch and from memory reflects what is showing in post analysis in the app.

For the life of me I haven’t been able to get the S+ app (or post analysis) into the red zone or even stay prolonged in the yellow zone. I would’ve hoped prolonged threshold efforts would take me there.

VoiGAS

@FCDsh Yes, I had the same problem on one exercise and believe the belt wasn’t sitting well, even if the HR was always measured. Next training I took more care and the values were back in the normal range

halajos

I just did my first 50 mile race and decided to control my effort with ZoneSense. It seemed to work pretty well, the zone or displayed aligned well with my feeling when running or hiking up a hill. I noticed something though, which I don’t know how to interpret. When I was running and decided to switch to walking for some reason, ZonSense showed that I went to anaerobic zone even though my heart rate was declining. When switched back to running, my HR started to increase end ZS went back to aerobic. Is there a reasonable explanation for that?

Audaxjoe

@halajos well done on your first 50 mile race

Radim Stengl

@halajos I have the same problem. I am not able to get in yellow zone at all. As my pace increases or I start to run uphill, I fall even deeper in green zone even if my HR is climbing up. Any idea how to interpret it?

Mff73

@Radim-Stengl
How long are you staying in expected zone (HRzone)?

Mattg576

@Radim-Stengl

I’ve been using Zonesense since it’s release & also saw it regularly drop off as my effort increased as you describe.
It does seem less frequent now so maybe it ‘calibrates’ the more you use it but it’s still present as can be seen below, I’d also be interested if anyone can explain why ?

(even stranger as it is complete opposite to what @halajos mentions above)

droopsio

Hi,

I have a problem with an app on the watch (Suunto Race S). As you may see on the photo, graphic widget display never changes from green to yellow/red - even in case, that I’m running with higher intensity.
After the workout is finished and saved, in the summary presented by app you can see, that I have been yellow/red zones, but it is never displayed on the watch while doing activity.

Additionally to this - for the whole time, I have a notice about warmup calibration.

Is it a bug for Race S series, or there’s something wrong with my watch?

In the example photo you’ll see, that some part of activity was made with higher intensity but it was never presented with marker and color (nor the stripe or edge).

halajos

@Radim-Stengl when I’m running I do see ZonSense going from green to yellow and red as intensity increases. To me switching between easy running and waking, as I do during an ultra trail, is confusing in ZonSense.

Ze Stuart

@halajos it’d be interesting to see a plot comparing HR, HRV, and ZoneSense.

halajos

@Ze-Stuart here are some screenshots from SA. The first one is the first hour of the race, when ZonSense showed I was in aerobic zone up to about 150 BPM. I haven’t had a threshold test since last year, at that time my AeT was measured 148 BPM. For this race ZoneSense tells my AeT was 140 BPM. The second screenshot is from later on the race, when ZoneSense shows I go from aerobic to anaerobic when I decrease intensity and my HR drops. Maybe it doesn’t work well with fluctuating intensity around the threshold.

far-blue

In the video explaining how ZoneSense works, Suunto basically describe how there are changes in the patterning of the variability between beats that the technology is looking for. So as the variability (the scale of variation in time between beats) shifts from quite high to more narrow (aerobic to anaerobic) and then again to more of a negatively correlated pattern (VO2Max) ZoneSense spots the pattern change and interprets it. However, I do think there is a level of personalisation / tuning going on as you use it more (and I suspect this doesn’t happen on the watch but in the app and is then sync’d back as a set of tuning values).

Also consider what happens when your actual heart rate changes rapidly - in these cases it would be hard for ZoneSense to differentiate between high inter-beat variability (i.e. aerobic zone) and a rapidly decelerating or accelerating heart rate. I think that’s what causes the sudden drops into aerobic on ZoneSense when you accelerate into an interval or switch from running to walking.

Ze Stuart

@far-blue this is why I was thinking it would be interesting to see @halajos’s HRV data as well as the ZS and HR data.

Ecki D.

@FCDsh said in Suunto ZoneSense:

I have noticed that the ZoneSense DDFA index values are displayed in the range 99-101, although the screenshots here in the forum show values with “0.x”. Does anyone have an explanation for this? Also, I can’t explain why the workout is classified as 100% aerobic even though I trained in higher heart rate zones? Does the algorithm need to learn more here?

Same here, was trying to get a measurement for anaerobic threshold and was running in Zone 5 (160bpm+ for me) in for about 10 minutes but suddenly no HR was shown anymore, even if it seems to be recorded and I only got 8 seconds in vo2max.
At the moment I can’t say ZoneSense seems very reliable to me but it has been my third run with it up to now.

Brad_Olwin

@Ze-Stuart A deep dive in the HRV data would be necessary, this would not be obvious from the HRV readings. Kanniainen et al. - 2023 - Estimation of physiological exercise thresholds based on dynamical correlation properties of heart r.pdf