On Fenix 7 Pro, why the wrist heart rate sensor does not turn off when an external chest strap is connected? FW 16.22

It would make sense, since most of us don't want in any case to have lack of data in the traces...somebody on Reddit was mentioning a safety feature for Garmin Pay (to sense a wrist -off action) but this explanation makes more sense and would explain the behavior also without Garmin Pay activated.

I just asking myself what it would mean in terms of battery consumption....even if elevate v5 looks have a low effect on battery drain during activity.

Before the firmware update that was right. It was only active for Garmin Pay.

mastermind88 said:

what it would mean in terms of battery consumption

Nothing noticeable in my experience. 

mastermind88 said:

It would make sense, since most of us don't want in any case to have lack of data in the traces

Except that most ppl who use an external chest strap in 2024 do so either bc the quality of the data is perceived to be better than OHR or they’re not wearing the watch. Considering the recent complaints about bad data from OHR, maybe it’s not unreasonable. I could just as easily argue that anyone who goes out of their way to use a chest strap would rather have missing data than bad data.

mastermind88 said:

somebody on Reddit was mentioning a safety feature for Garmin Pay (to sense a wrist -off action) but this explanation makes more sense and would explain the behavior also without Garmin Pay activated.

According to Garmin themselves, both explanations are true.

https://forums.garmin.com/beta-program/fenix-7-series/f/community-discussion/360515/hearth-rate-problem/1737727#1737727

Garmin-Laurie said:

I do understand the concern with the battery life, having the OHR enabled while using the HRM. However having this enabled is by design. The change is for a couple reasons. The first is consistency in HR/HRV throughout. So if one HR method is dropped, the other will pick is up. The 2nd reason is for Garmin Pay. When your OHR is disabled during activity, Garmin Pay cannot be used without a PIN code, because the watch is treated as "Off-Wrist". So keeping this enabled, allow Garmin Pay to be used during activities. 

The elevate V5 on the f7x pro looks pretty accurate so far (at least from mynreltive short experience with that watch Vs my old instinct 2)...but of course a well placed/wetted HR chest sensor is way more superior in accuracy.

It's better than it used to be but it's still extremely slow and inconsistent for intervals and anything else where HR fluctuates rapidly.

5925888 said:

it's still extremely slow and inconsistent for intervals and anything else where HR fluctuates rapidly.

And that will always be the case to a certain degree. The heart lags anyway whenever intensity is changed. There is no abrupt, instantaneous increase in heart rate when an individual suddenly breaks into a sprint. With very short sprint intervals, it is often the case that the heart rate has not had time to register the demand before the sprint finished. This means the heart rate will not reach the intended intensity before it reacts to the decreased demand from the return to a lower intensity. Heart rate dynamics are very individual. That means a very fit individual used to sprint interval training can expect to see the heart respond quicker to changes in intensity than someone who does sprint interval training intermittently. Even then, well-trained individual will still not see the heart reach the intended level commensurate with the interval target. 

A strap will respond quicker to changes in intensity as that detects the electrical signals of the heart beat whereas the optical heart rate has to wait until there is a change in the blood volumes detected at the wrist. But both will always lag.

The same for me on 16.22 on Fenix 7Pro. When I connect chest strap , wrist sensor still On. Only the way is manually switch it off. Not sure how about others, but for me wrist sensor on 7pro work not good specially when I running. I had before Fenix 6 and wrist sensor was working much, much better. I have tested and yes, it take HR from chest strap, but in parallel Wrist sensor running. When I take off chest sensor , it took ages when the watches again show heart rate from wrist.... So the backup function looks not really good. I'm getting suspicious that only the reason for this is that Garmin would compare data from chest and wrist for own internal purpose to know how the wrist sensor is good or bad.

I have defined a new mode with the power manager for all my gym activities where I use a chest strap and have deactivated the wrist HR. A second mode has wrist HR enabled in case I forgot the chest strap at home.

But I think that is no real issue for power consumption at all. I have HR on 24/7 and the Descent MK3 51mm lasts for 2 to 3 weeks with one charge. I guess the watch is comparable to a Fenix 7X

Before I had a Fenix 6X pro that was equally good in power consumption.