The review from The Quantified Scientist is out for the Fenix 7 (Youtube)

Geroelltrampel said:

For exact results you may be right. I think nobody expects exact results like from lab instruments, but it makes me wonder why Garmin provides these measurements if they are even not as good as many cheaper watches as you could see in this review.

We saw the same discussion with OHR with Fenix 6. Some stated that its totally out of range even compared to cheaper competitors, than the fanboys said "Get a cheststrap" - which is right, but pointless in this context.

The problem is, whenever it comes to critizise some aspects of a shiny expensive new Garmin product, the fanboys get mad and try to draw the discussion to pointless aspects or trivialize as best as they can. "Oh for me I never experienced jumping pace, I never noticed any deviation in GPS, I don´t notice reflections on screen as I got used to it" and so on.

Its very ok that some people lower their demands until they are perfectly satisfied with anything Garmin offers. But they should be aware, that to some other people a 1000€ watch sets expectations a little higher than a to an 40 bucks Amazfit Bip S.

I totally agree with you. Either a feature works within a narrow margin, or it doesn't make sense. If most calculated values rely on an accurate HR, what are they worth if HR is not really that good, and could be better, as Apple proves?

Also, Garmin's laissez faire attitude towards accurate values can well be observed right now regarding their altimeter / barometer calibration, which they broke, but don't really care about.

So, really, it's just nice graphs and a shiny vO2max value for the dopamin hit.

Geroelltrampel said:

but it makes me wonder why Garmin provides these measurements

Honestly I agree, and wonder the same thing - personally I think they should just nix the sleep phases from the Fenix line altogether, it doesn't add anything positive to the user experience (especially if the data isn't reliable, but arguably also even if it was reliable), and I think people would be a lot happier not having the function at all, versus having the function but not working as well as they hoped.

I'm perfectly willing to criticize things about the watch, and I don't need to justify my purchase to myself since I am still well within the return window if I had buyer's remorse. This just isn't a feature that I care about whatsoever, and frankly I wonder why such a large portion of users do seem to care about it. I get the argument that "it's an expensive watch, and all the features that it has should work flawlessly", and it's a valid argument, but that's also why I think Garmin should just ditch the whole sleep phases shtick altogether - that way, it will be a step closer to having all of its features working the way people expect.

And then of course there are the people who simply don’t want to hear anything good about Garmin too.

The bigger problem is most of the Garmin's exclusive features depends on OHR and sleep tracking (body battery)

Body battery does not utilize sleep phases at all. It uses HRV/stress.

Dr Phil said:

PEople often forget that OHR is not measuring the heart beat. It’s estimating a value from the change in color as blood pulses through under the skin.  It is not a measure. It’s a calculation. Only a chest strap measures the heart rate. 

Poppycock. Both are measurements needing processing. An ECG wave per se is not a heartbeart, you have to pick out the R-peak. In the same way you have to interpret a pulse wave. One works with light, one electrically, both end up in analogue-digital conversions. There is simply more noise with a pulsewave, and less with an ECG.

www.researchgate.net/.../Radial-arterial-pulse-pressure-wave-and-ECG-a-the-typical-pulse-pressure-wave-marked.png

Don't agree with this one... Though i understand that you may not be interested, and that's completely fair, I am and would like my watch tondo it a little better. Also ,i think it's fair that a function or an algorithm is not perfect and needs improvement, also though experimenting on the user base.

Probably would be good to have the possibility to switch it off indipendently from other measurements, though, as such who is not interested could get rid of it 

By all means posit an alternative theory but do recognize there is a difference between a pulse pressure wave and photoplethysmography. A pulse pressure wave is not what OHR looks at to estimate heart rate - How optical heart rate works. The electrical signal from the heart presents a much more definite peak that can be easily observed and measured, hence why a strap should be the preferred method for 'active' activities.

BTW, this was from a workout this morning combing running and some bodyweight strength exercises on two watches, one recording to a HRM-Pro (Epix Gen 2) the other using WHR (Instinct).

I find the HR to be more accurate, less prone to spikes than the fenix 6 so I am happy.