Fenix 5 : advanced analytics/features that require an HR chest strap ?

Unless I've missed that discussion, surprisingly little (nothing ?) has been said about the requirement to use an HR chest strap instead of the optical HR sensor to get the new and advanced analytics offered on the F5.

Looking at https://buy.garmin.com/en-GB/GB/p/552237/pn/010-01685-13#overview it seems that the optical HR sensor will be able to deal with :
- Training Status
- Training Load
- Recovery Advisor (like on the FR235)

Chest strap required :
- Stress Score

TBD :
- Lactate Threshold Test : chest strap likely required as that's already the case on the FR735XT
- Functional Threshold Power : ?
- Training Effect 2.0 with aerobic and anaerobic benefit scores : ? but that would normally rely on HRV so needing a chest strap at this time
- Performance Condition : calculated after about 10' of running and then logged in the fit file/GC

Has anyone else been wondering about this ?

0 Former Member over 8 years ago

That's correct, which raises a few questions concerning the "performance condition"

No need to guess/wonder. Garmin explains how it comes up with the number...
http://www8.garmin.com/manuals/webhelp/fenix5/EN-US/GUID-901ACCFC-FB0D-414E-B80C-54970AF4E357.html

Per Garmin, the Performance Condition measurement is based on "pace, heart rate, and heart rate variability ... compared to your average fitness level." And it goes on to say that "average fitness level" is based on your VO2 max.

0 webvan over 8 years ago

Once you've re-read the entire message you quoted and therefore become aware of the fact that oHR sensors do not provide any proper HRV data you'll hopefully give it more thought.

0 Former Member over 8 years ago

Once you've re-read the entire message you quoted and therefore become aware of the fact that oHR sensors do not provide any proper HRV data you'll hopefully give it more thought.

HRV is (essentially) just a rate of change for your heart rate. If you can measure heart rate, you can determine/estimate HRV. The "reliability" or "propriety" of the HRV measurement may be questionable, but so is any measurement from wrist-based heart rate sensor... particularly during vigorous exercise where these additional metrics would be most useful.

0 webvan over 8 years ago

Wrong, HRV is based on "r-r" intervals -> http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=149812

0 jminar over 8 years ago

What is an r-r interval?

0 Former Member over 8 years ago

Wrong, HRV is based on "r-r" intervals -> http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=149812

Yes I know it's based on intervals. That's why I said "essentially." A "rate" and and "interval" are just two ways to convey the same meaning. I was speaking in terms of rates because it's more intuitive. The point is, HRV is just a measure of how the heart rate changes over time. If you can calculate HR, you can calculate HRV.

0 R_Tellis over 8 years ago

Yes I know it's based on intervals. That's why I said "essentially." A "rate" and and "interval" are just two ways to convey the same meaning. I was speaking in terms of rates because it's more intuitive. The point is, HRV is just a measure of how the heart rate changes over time. If you can calculate HR, you can calculate HRV.

That's not true. A rate of 60bpm can have one beat every second which would be an r-r interval of 1 which is basically no HRV since there is no variability in the heart rate. What is more normal is that with a rate of 60bpm the beats would come at intervals like 0.98, 1.02, 0.96, 0.99, 1.01, 1.04, etc... and the greater the variability of those intervals are the higher the HRV is.

In both cases the rate is 60bpm but they have different HRV values and it's the measurement of these intervals that optical HRM is not good at although some manufacturers claim they are getting it "good enough" now to offer HRV estimates. That is why Garmin is now offering the continuous Stress Score on the VivoSmart 3 and, according to DC Rainmaker, it's being brought to the F5 series and the 935.

0 webvan over 8 years ago

Yes as seen in the link above the r-r intervals at rest produced by the FR235 are meaningless. There is some talk that "some manufacturers" are now able to get meaningful data "at rest" which seems very dubious on what comes out of the FR235 at least as far as Garmin is concerned

The whole "stress analysis" of the VS3 is not very impressive either when you think of it, just look at the heartbeat rate OUTSIDE of sports and you've got your "stress".

0 Former Member over 8 years ago

That's not true. A rate of 60bpm can have one beat every second which would be an r-r interval of 1 which is basically no HRV since there is no variability in the heart rate. What is more normal is that with a rate of 60bpm the beats would come at intervals like 0.98, 1.02, 0.96, 0.99, 1.01, 1.04, etc... and the greater the variability of those intervals are the higher the HRV is.

In both cases the rate is 60bpm but they have different HRV values and it's the measurement of these intervals that optical HRM is not good at although some manufacturers claim they are getting it "good enough" now to offer HRV estimates. That is why Garmin is now offering the continuous Stress Score on the VivoSmart 3 and, according to DC Rainmaker, it's being brought to the F5 series and the 935.

Yes, but the fact still remains that in order to measure HR, you need to measure beats over a time period. So if you can measure beats, you can measure the time between them, which is HRV. That's all I'm saying.

0 Former Member over 8 years ago

Functional threshold power requires a power meter, the Fenix 3 already supports that for cycling if you have one.

As for the others I imagine they will require a chest strap. If Garmin had managed to reliably measure HRV using optical I think they would have said more about it since no one does that reliably yet.

Right I hadn't paid close attention being a runner but FTP is not HR dependent.

FTP isn't HR dependent, but Firstbeat's method of detecting your FTP relies on HRV. (Garmin just licenses the software from Firstbeat.) The white paper is a little vague, but it sounds like it works like LTHR detection:

How does it work?

To calculate your FTP, the Firstbeat analytics engine requires a stable VO2max estimate and enough quality heartbeat data recorded across a range of different intensities from low to high. Because external workload is a factor in the calculation, you will also need to ensure your bike’s power meter is connected to your device. Data can be gathered during a guided test specifically designed to record the data needed to detect your FTP, or it can be calculated from normal running activities that include enough quality heartbeat data from each zone.

Once this data is obtained, the Firstbeat analytics engine identifies your FTP level by isolating the deflections in your heart rate variability that correlate to key indications of how your respiration patterns respond to the intensity of your activity.

https://www.firstbeat.com/en/consumer-feature/functional-threshold-power-ftp/

For what it's worth, the watch has detected my FTP twice in the three weeks I've owned it, both showing an increase of less than 5 watts. Both times the resulting intensity factors have made sense, so it appears to work based on my limited experience with it.