Instabeat and the Garmin 945 with oHR – first Swim with the new Betaware

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I had a ‘special’ piece of swim kit on today (INSTABEAT) but I’ve not yet managed to get the data off it (doh) so here is the HR chart sans ‘special kit’ and you will also note that this is my first use of the new beta software on the Forerunner 945 which FINALLY enables oHR for any kind of swimming.

I think this is probably my record (5)  for the most number of heart rate monitors worn when swimming and I have to say it was a bit embarrassing but, luckily, they were mostly hidden by various bits of swim gear.

The Polar OH1+ clipped onto my swim cap and the H10 recording onto the Polar Beat app via caching both worked in line with my RPE. As you can see both the Vantage M and Garmin 945 with oHR (beta) were wrong. Incidentally, I had both fully underneath each wetsuit sleeve which I would have thought would help accuracy.

My effort was a 30-minute swim that got progressively harder/faster in fairly warm water. It’s interesting that the Garmin 945 oHR shows a “stable” HR level rather than a rising one…I can’t explain that.

FWIW: Each watch produced a sufficiently acceptable GPS track of my swim.

The Instabeat device has a HUD showing my HR zone and did seem to show the right zone a the right time in a non-intrusive way. So, all is good on that front. I looked at the HR chart on their iOS app afterwards but the data was heavily smoothed so I’m not sure what details the smoothing might be masking. We shall see…



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When using the Polar Vantage and the H10, can you sync both the cached HR data and the GPS trace from the watch to Flow? If you can does it combine them into one activity?


Yeah, I was wondering about that as the V doesn’t like not having the Stryd around if you go for a run with out it (i.e. no power). It would be great if would default to the onboard sensors if it gets drop out/battery failure.


This is roughly in-line with what I got testing Scosche Rhythm+ vs H7 a few years ago. HR shown by optical could be stroke rate instead, thus more or less stable value.


That’s why an accelerometer is used internally to distinguish HR from cadence as the optical sensor itself only detects a mix of both.
They call it a “crossover problem”.