Hi,
thank you for your reply. I followed all your advices and here is in detail, what I found:
- Watch with enabled HR on watch, disabled Power Saving -> HR is shown in Activity screen; VO2 Max is present in Health
- Watch with enabled HR on watch, disabled Power Saving and connected external HR -> HR is shown in Activity screen (but it looks like HR only from watch is shown); VO2 Max is present in Health (but it looks like it is data from Watch sensor)
- Watch with disabled HR on watch, enabled Power Saving -> HR is not shown in Activity screen (but it is measuring and later, it is synced with iPhone correctly); VO2 Max entry missing completely
- iPhone connected to external HR, Watch enabled HR on watch, disabled Power Saving -> HR is shown in Activity screen (but looks like HR only from watch is shown); VO2 Max is present in Health (but it looks like it is data from Watch sensor)
Even if I put external HR monitor as 1st in line in priority screen of HR data sources, it has no effect.
So, based on my experience, I would like to ask some questions:
1 - do external HR monitor need to support also VO2 Max? I thought, that it is calculated completely by iPhone/Watch
2 - can I see somewhere on iPhone all features supported by external HR? So far, I found only one entry in HR data source as "Heart rate" next to external HR monitor
So, my problem can be divided to 2 sections:
a) when using combination Watch only, disabled HR on watch, enabled Power Saving and paired and connected external HR monitor, it is not shown external monitor's HR data in Activity screen (see 1st image, where there is no HR data displayed and 2nd image confirming, that external HR monitor is connected via Bluetooth and working)
b) lack of presence of VO2 Max data when using external HR monitor completely


Thank you for your patience about this issue so far.