Suunto ZoneSense

[Oxhill_Runner]

@Theo-Lakerveld
Hi Theo
I followed @Brad_Olwin advise this weekend on a 2hr trail run with a lot of climbs. I noticed a similar trend to yiur data in that the DDFA score increased to a max at the start of a climb (a drop on the graph) before dropping and going negative after the summit.

Anyone know why this happens? You can see a clear lag between DDFA and HR which I can understand but why does your DDFA improve when HR increases initially? Just curious !

[Brad_Olwin]

@Oxhill_Runner DDFA is not measuring HR. There is a lot of information about this from Suunto.
https://youtu.be/bD3O4BZ9vIc?si=JXKmquFxU2TXahXx

[Oxhill_Runner]

@Brad_Olwin
Hi Brad

I get that it’s measuring HRV, something I’ve been tracking with HRV4Traing for a few years now too.

I was curious why the DDFA score improves initially as intensity (and so HR) increases before decreasing and ZS moves out of aerobic towards anaerobic zones.

Seems a bit counter intuitive that’s all ! Maybe a question for a cardiologist

[Brad_Olwin]

@Oxhill_Runner you are only seeing one example and when HR increases ZS will not always increase, more complicated. That is why I gave you the video link. ZS does not measure HRV as the app you use. What you are asking is not necessarily occurring. However, there is a lag between ZS and HR.

[herlas]

@Brad_Olwin @Oxhill_Runner, I’ve seen that behavior consistently with ZS about having a big drop to positive value (green) at the start of a interval.

From what I’ve been reading, it’s all about a reaction reflected on our HRV when we introduce a big change in intensity, our HRV changes and kind of prepares for what is coming.

This can also be seen when you’re about to start a downhill and change intensity.

Point being, those big drops to green are related to times where are intensity shifts by a lot.

This is from a 3x15 mins @ threshold:

[Brad_Olwin]

@herlas Yet at every drop you have a substantive decrease in HR. I think if steady HR and progressively increasing these will not occur.

[Theo Lakerveld]

To me, it looks like the ZoneSense reading follows lactate build up. I’m going to test this with the lactate measurement protocol from the trainers in the Norwegian triathlon federation (the people behind Blumenfelt and Iden). I have a lactate level blood test device. If the test result follow each other, this could be a really revolutionary functionality. I’ll keep you posted.

[herlas]

@Theo-Lakerveld have you looked at the webinar videos put up by Suunto on their YouTube channel? What you’re mentioning on ZS and lactate thresholds was already stated as a finding, ZS does follows that and Monicardi who came up with DDFA Index used in ZS, said ZS is +/- 5 bpms to heart rate in a lactate threshold test.

Nothing really to demostrate here anymore, but give it a try for yourself

[Theo Lakerveld]

@herlas nope, I haven’t seen these. I’ve only read the superficial marketing stuff. I usually don’t trust that stuff before I’ve seen proof or have experience with it myself. So therefore I’m getting happily surprised with the ZoneSense functionality.

[halajos]

I’m curious to see a comparison of lactate levels, HR and DDFA index on the trails. I’m getting green ZS on uphills taking more than 3-4 minutes when I feel I’m working harder but not pushing hard and my HR is reaching my LT. Based on the HR I should be in yellow/red in ZS, but maybe flat running HR “zones” don’t apply to running on terrain with elevation change.

[Brad_Olwin]

@Theo-Lakerveld There are peer-reviewed scientific manuscripts published on this with much more sophisticated lab testing than you have but you are welcome to test.
Kanniainen et al. - 2023 - Estimation of physiological exercise thresholds based on dynamical correlation properties of heart r.pdf

[Brad_Olwin]

@halajos I am getting expected behavior on hills. I only have hills for running:)

[halajos]

@Brad_Olwin good to know, thanks. I’ll continue experimenting once my MCL injury allows. Do you need to maintain a very stable HR (which often doesn’t happen due to small changes in terrain)?

[Brad_Olwin]

@halajos No, my HR changes dramatically depending on the workout. Today will be Tempo uphill so higher HR and fluctuating. I will run the intervals based on RPE, just below my LT, which I can easily determine based on my breathing. On an Endurance run I use ZS to stay in the Aerobic zone and slow down if I enter the Anaerobic (Yellow) Zone no matter my HR, which I am not observing.

[thanasis]

Can someone explain how this can be the case ?

It’s the second time I get those kind of values as if zone 3 and 4 would be essentially one

[halajos]

@thanasis your Z4 minimum is set manually in the HR zones settings, while the aerobic threshold is measured by ZoneSense. Probably you need to adjust your zones.

[thanasis]

@halajos said in Suunto ZoneSense:

@thanasis your Z4 minimum is set manually in the HR zones settings, while the aerobic threshold is measured by ZoneSense. Probably you need to adjust your zones.

thank you . however i am not sure what should i do considering that the minimum Z3 according to Zonsense is supposed to be higher than the minimum Z4 .

[jussim]

@thanasis You obviously need to increase zone 4 and zone 5 limits. How confident are you about what you have set as max Hr?

[The_77]

@thanasis I had much the same last Sunday, and my zone 2/3 boundary is similar to yours.

Usually my aerobic threshold ranges from as low as 120bpm to upper 130s - at no point has it ever gone up to 156bpm, and I wonder if it struggled with the specific workout type I did, which was a gentle warmup, some strides, and then 12x 3:30 with 1:30 breaks.

You can see that it enters the VO2 threshold at around 163bpm repeatedly, and obviously it enters Anaerobic when I’ve already been at a high HR for the previous couple of minutes, hence pegging the aerobic limit as being so high I guess. Food for thought anyway, most likely ZS can’t cope with intervals being so short as per the documentation.

[Brad_Olwin]

@thanasis said in Suunto ZoneSense:

@halajos said in Suunto ZoneSense:

@thanasis your Z4 minimum is set manually in the HR zones settings, while the aerobic threshold is measured by ZoneSense. Probably you need to adjust your zones.

thank you . however i am not sure what should i do considering that the minimum Z3 according to Zonsense is supposed to be higher than the minimum Z4 .

I have similar ZS results and our HR zones are very similar too. I am leaving my zones where I feel comfortable with and essentially not worrying about them! They are arbitrary anyway! Even a lab measured LT test is going to vary depending on your fitness, recovery, fatigue and stress the day you are tested. I believe that ZS is giving me an accurate representation of my effort based on 16 years of running ultras. I will likely never adjust my zones again and essentially ignore them.

My interval efforts are based on RPE anyway and now long runs and recovery runs will use ZS. So it doesn’t matter if my LT is 120 bpm one day and 148 on another day. This is the reason to use ZS!