Intensity minutes

- said:

So far I was told about 150% and 200%.

Those numbers are valid for me. As I wrote, they may differ at others, depending on the watch model (though I do not really think they do), and also on the age, weight, height (those factors are mentioned in the support document How Does the Intensity Minutes Feature Work?), and perhaps also on the max HR (although not mentioned in the document, it would not be surprising at all). I did not verify the influence of the max HR experimentally, but if it is really important to you, just do the test, it is not complicated.

As for the max HR, make sure you test it using the HRM chest belt, since the OWHR may lock to your cadence instead of the HR, giving you so false data. Also make sure you do not just pick the top peek of the HR from your stats. Have a look for example at the following video for the detailed instructions how to detect your max HR properly:

BTW, the daily graph shows the HR with the interval of 2 minutes, so even if it often appears that there are frequent periods, when the HR is above the IM threshold, the reality may be quite different, because during the 2 minutes the HR might have easily dropped down and raised again, resetting so the counter of the required 10 consecutive minutes.

All in all, getting 69 IMs for a day like the one shown on the graph, seems to be perfectly fair to me. 

I will download the hr data track and will check the second by second data. Certainly it will be just a proxy, because these are from hr strap, and not from owhr.

I have a different conclusion than you, and I can explain the validity of 65 IMs only if I involve the mysterious inclusion of max hr.

- said:

I have a different conclusion than you, and I can explain the validity of 65 IMs only if I involve the mysterious inclusion of max hr.

It is not different. It is what I mentioned as a possibility

I truly appreciate your efforts you made to share your opinion. I also feel that you also a sort of guy who is trying to dig down to the primary information sources.

Frankly speaking it helped me to answer my own question which method of IM calc may be better.

I think from a physiological point of view  max HR should have nothing to do with intensity minutes. And maybe RHR should not either, but as regards including RHR I have ambivalent thoughts.

Eg. I have a pectus excavatum, so as a consequence smaller lungs than normal. I guess and so did my cardiologists and pulmonologists, that my heart simply compensates my partly defunctioning lungs. I surmise it is the reason of a high max HR. 

But all my thresholds, either you call them LT1 & LT2, or AT & AnT, or LT & IAS & ANS (the last is a German terminology) has nothing to do with my max HR, neither with my RHR. The ratio between them and max HR  vary too much between individuals.

Properly set HR zones may have something to do with IM.

Age, weight, height may have also if you use a statistical database to estimate the HR zones of an individual. But in this case you have the same inherent error as in case of using RHR and max HR, so heart rate reserves.

Until now I accepted a usage of RHR as the primary factor behind defining whether you are doing something intensively, because the purpose of counting IMs is not about how intensive your life was in that particular moment, but about whether you simply was above some threshold when your body starts to work in a different way than during resting or very moderate moving.

Now I think it is simply better to link IM calc to my HR zones.

EDIT: I totally disagree with the method the video proposes as regards defining max HR. Either you follow the advices of those including Joe Friel who say that it is unhealthy to find out your max HR, because it streches your body too hard, or you do a proper vita maxima test, and at the time of a full exhaustion when your body really hurts, your lungs are like burning, then you get to your max heart.

I agree that you can have a sort of smoothing, not to simply pick the max data, but only in case of using ECG/EKG as a HR measurement tool. Your HR strap itself does a smoothing of your real instantaneous heart rates. So it makes no sense not to pick the max data

I say these, because I had several lab tests when I collected my heart rate data with my strap, while the exercise physiologist relied on the ECG/EKG. And I saw that my HR data collected by them were really jumpy. 

- said:

Your HR strap itself does a smoothing of your real instantaneous heart rates.

The HRM belt does not smooth anything. It even reads the HR Variability between individual systolic peeks, and that is also used for a multitude of features. Something else is than the recording that is averaged to 1s or longer intervals in the activity file, and to 2 minutes intervals in the daily HR monitoring file.

Well, that is off topic here, let's come back to the IMs - I just conducted two more tests on an indoor bike. Unlike the last test, that was done a year or two ago, on the old Garmin Instinct, this one was done with the recent Garmin Instinct 2. In both cases my settings are practically the same - I use the default IM method (in fact on Instinct 1, there was no other option).

At the first test, I kept my default settings - HR max of 182 bpm, and my avg Resting HR is at 55 bpm today. started pedaling with a steady effort, trying to keep my HR stable, very slowly gradually increasing the effort, and hence also the HR. The IM's started to increment after couple of minutes. Unfortunately, I've been moving too much before the test, so my HR was over 80 bpm already before I started, so could not measure the 10 minutes delay or the exact threshold, but looking at my daily HR graph, it matched my previous results - the threshold is roughly at 150% of the RHR (~80+ bpm). I continued increasing the HR, to detect the vigorous IM threshold, when the IM increments start to double. It happened around ~125 bpm, hence rather around 220-230% of the RHR. 

I then stopped the activity. changed the HR max value in the device User Settings to 220 bpm, and synced the watch to get it there too. I repeated the test, and came to identical results, as at the first test.

Well, I changed the HR max in the global HR setting of the watch. I should repeat it also for the HR max in the Cycling HR profile, and should also try changing the LT values, and HR Zone settings to see if the also have no impact on the IMs, but that would require quite a bit more time, so I let t for those who really care more than me about it, since I am rather satisfied knowing how it works for myself

And now I checked the release notes of 19.20 and it says that 

• Updated Intensity Minutes determinations to align with guidance from CDC.

And enjoy this one, too: The Influence of Removing the Ten-Minute Bout Requirement on National Physical Activity Estimates (cdc.gov)