Subject: Feedback on Zone Sense accuracy: Short intervals and Zone 2 threshold shifts
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A simple copy-paste? Seriously? That’s it
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In the areas where Zone Sense marks the curve in red (anaerobic), I was clearly in zone 3. I could count or recite the alphabet without any trouble, yet the watch showed me at the absolute limit of the red zone.
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@Dieter1960 VO2M in ZoneSense VO2M spans from your LT to your max, so potentially a large range. You could be right at LT with red ZoneSense and would be able to say a few words.
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@Dieter1960 said in Subject: Feedback on Zone Sense accuracy: Short intervals and Zone 2 threshold shifts:
In the areas where Zone Sense marks the curve in red (anaerobic), I was clearly in zone 3
Today ZoneSense determined my LT (anaerobic threshold) at 131. That is the bottom of my Z2, just above Z1. My true anaerobic threshold is somewhere around 161-163. This is ridiculous! I was hiking up at easy effort for the first ten minutes. My muscles were fatigued after yesterday’s effort, but that isn’t the reason for it to be so wrong because aerobically I wasn’t stressed at all.
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@Brad_Olwin said in Subject: Feedback on Zone Sense accuracy: Short intervals and Zone 2 threshold shifts:
I do not know what HR belt you are using.
I use Suunto HR belt, and it is reasonably new, perhaps 4-5 months old, and I don’t use it that often. It was the same with Polar H10 before.
If I have a truly easy run. ZS remains green. But usually those are Z1 jogs with my dog where we do a lot of stops. But if I am trail running and putting some effort, my ZS graphs are always messed up like in the example above. I think it confuses the muscular stress with the aerobic stress. Aerobically I am well developed and my HR stays in Z1 and Z2 most of the time with occasional Z3 and Z4 and almost never Z5, but according to ZS it is red a large percentage of the time. I guess I am an outlier and ZS simply doesn’t work for me.
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Another strange ZS chart from my yesterday’s 30 min treadmill run. First a 10 min warmup on 8, then gradual increase to 13. Somehow ZS claims that running at 5:29 is more challenging for me that at 04:46. Also a 2% VO2max effort?
While the chart is not even touching that zone…
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@cheetah694 ZoneSense isn’t aware of your speed, effort you put in, not even your current heart rate. It applies statistical calculations on a series of your individual beat-to-beat intervals (time between subsequent beats of your heart). If the statistics show a certain pattern, ZS will show you the respective zone. So its accuracy depends on, in addition to the applied algorithm, the quality of the data received from the HR belt, and your individual physiology.
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@halajos Yeah, fine. I have a feeling I’ve read and heard enough of it. My next buy will be a lactate meter.
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@cheetah694
AI analyse of a fit file (run) especially the record.cvs file from it :The Data Verdict (DFA a1)
• Why Garmin is right: Raw data from your record.csv file shows your Aerobic Threshold (VT1) is at 148 bpm, exactly when the heart rate complexity index (DFA a1) hits 0.75. Garmin uses this value to end your Zone 2, matching your real-time physiology.
• Why Suunto is wrong: Suunto sets your threshold at 130 bpm. At this heart rate, your data shows a very high DFA a1 (>0.85), proving your body is still in a state of ease. Following Suunto would unnecessarily restrict your training.
• Anaerobic Threshold (VT2): Your data also confirms you enter the critical (anaerobic) zone at 161 bpm (DFA a1 = 0.50), once again validating your Garmin Epix settings. -
@Dieter1960 said in Subject: Feedback on Zone Sense accuracy: Short intervals and Zone 2 threshold shifts:
Analyzed the data through a specialized AI model to identify physiological breakpoints
I’d be curious to know which model you used. If you ask an LLM to interpret your R-R data it generally uses the same (or similar) model that DFA-alpha1 is based on, but you can then tweak the prompt to ask it to compute the data using an “adaptive” model that should be more similar to what Suunto uses. At least this is something I tried long time ago, and eventually the computation was too heavy for the model to produce a result. AI models have evolved enormously since then.
Nevertheless, I no longer look at ZoneSense data during my runs, simply because it just seems to “adapt” to my intensity. If I run at my typical aerobic effort, the shift between green and yellow is very likely where I expect it to occur, but if I run something more demanding (trail, tempo, race, etc.) it puts me in the aerobic zone when I actually have ±10 bpm above my aerobic runs.
