Suunto ZoneSense

Oxhill_Runner

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)?