Does Forerunner 45 support hrm run strap?

You can pair an external HRM to it.

I'd expect the HW for OHR is the same or close.

I've found out that it doesn't fully support it - I'll be having to post a separate question, as the HRM dual does give R-R timings as well as the basics of heart rate, but the forerunner 45 doesn't support the transmission of that over ANT+.

Not sure what you mean by this Dave:

DaveBarber said:

HRM dual does give R-R timings as well as the basics of heart rate, but the forerunner 45 doesn't support the transmission of that over ANT+

The Forerunner 45 supports HRV tracking, as indicated by the FirstBeat site: firstbeat.com/en/consumer-product/garmin/forerunner-45/

It's got the "All Day Stress" function which is the abstraction layer for HRV stress (r-r interval). "Body Resources" is driven by that and labelled as "Body Battery" by Garmin.

Ergo, the 45 measures HRV using the built in optical HR sensor. R-R Interval (HRV) is a requirement for all ANT+ chest-strap HRMs. Unless I'm missing something, the 45 does track HRV from a chest strap.

Transmission of R-R interval is not supported over ANT+ for many chest straps, the Garmin HRM Dual is one of the few that does actually support that.

I bought a HRM dual as it would give me accurate heart rate whilst rowing, and support R-R transmission.  But the forerunner 45 does *not* pick up the R-R data over ANT+, it only picks up the heart rate.

How do I know this?  There are blanks in the stress details from when I have the HRM Dual connected.

So the 45 does not track HRV from a chest strap - or at least not from Garmins own HRM Dual chest strap.

Dave: are you connecting to the HRM-Dual via Bluetooth or ANT+? BTLE doesn't mandate HRV transmission, ANT+ does - it's right in the spec.

The 45 doesn't support HRM over bluetooth, it only supports ANT+.  And the 45 clearly does *not* support R-R over ANT+.  I'm talking about what it actually does, rather than what the spec claims - Garmin seem to have missed it off their own device.

DaveBarber said:

The 45 doesn't support HRM over bluetooth, it only supports ANT+.  And the 45 clearly does *not* support R-R over ANT+.  I'm talking about what it actually does, rather than what the spec claims - Garmin seem to have missed it off their own device.

Jebus. That's... awful. Massive oversight on Garmin's part here.

I kinda want to borrow an FR45 and try it with a Polar H10 to see if that works. (H10 is my go-to HRM these days after too many failures of Garmin HRMs)

It'll be interesting to hear how you get on; the HRM Dual is a good and reliable chest strap, the way it connects seamlessly to the 45 is wonderful (I always seemed to have issues with bluetooth devices).  And it is definitely accurate too.  But just a very strange omission.