Discrepancy in HR data between daily and 4-week chart

Could you post a screenshot of the 4W Max HR Report too? (https://connect.garmin.com/modern/report/13/all/last_four_weeks)

Which Garmin device do you use, and which strap? If it is HRM-Pro, or HRM 600, do you use the HRM strap also standalone, without the watch?

Marek said:

I found other threads reporting exact same issue and it was linked to the HRM Plus strap recording some artefacts after being taken off the chest. 

Yeah, I once saw a very high fake HR reading (around 220 bpm), when I took off a chest strap after a run and rinsed it with water, while it was still connected to the watch. The way to prevent this is to make sure you close any activity before taking off your chest strap, to ensure that the chest strap is disconnected. (At this point, you should also avoid using the HR widget/glance, because opening the glance will cause the strap to reconnect.)

I think I've also heard of fake HR readings from an HR strap that's just sitting in a gym bag. So I think to be safe, you want to make sure that the strap does not connect while you're not wearing it. If you need to be 100% sure of this, you could always explicitly disable the HR strap connection in the Sensors menu, when you are not using the strap.

I always disconnect one of the press-studs when I take off the HRM. 

Hi. Thank you for the comment. I think the problem with HRM Pro Plus is that it would record the erratic readings ones taken off and the upload after reconnecting. Can it be even stopped at all?

OK. Sorry I missunderstood. You phisically disconnect it from the strap? That is an idea...

There is really nothing in my exercise data to support these odd 200+ spikes. 

Yes, I unclip one end from the strap. The HRM is normally hanging in my home gym and so my Fenix 7 will link to it whenever I am doing weights/yoga etc, even if I'm not wearing it. Disconnecting it from the strap prevents this. 

HRM Pro Plus cannot phisically disconnect from the strap unfortunatelly.