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FR235 HRM and Sleep Data Comparison

Hi,

I have received my FR235 yesterday and am currently in the process of comparing its HR data and sleep data to other products I have been using so far.

HR: Compared vs Polar H7 chest strap recorded by Polar Beat iOS app. I am using mygpsfiles.com to compare.
Sleep data: Compared to iOS Sleep Cycle Alarm app.

I thought I might share this here in a thread.... so here you go :) I will add new comparison-results once I have completed them.

GPS Run 02 Dec 2015, Beta 3.13

Blue: FR235
Orange: H7

My first ever run with the FR235, I was trying different paces including walking to see how it would react. Over all I am satisfied with accuracy.
- at around 14:00 I slowed down for the first time and the FR235 lagged behind with dropping HR again.
- at 25:00 I did a sprint... the FR235 was suprisingly accurate with this one
- at 33:00 it was a little more inaccurate, maybe because at that point I was slowing down again
- From about 52:00 I was just sitting down... there the FR235 was jumping a lot more up and down than the H7

0 philippe.berini over 9 years ago

Here's another run with FR 3.20.

Mostly same picture as for my other runs so far. The FR235 struggled twice when I first stopped to have a quick chat with a neighbour, and then in the second half where I just slowed down a tad. Could be cadence lock issue.

Otherwise, from being more spikey than the chest strap readings (as we already know), again it's quite good for my taste. Of course sometimes the spikes make it off than more 10 bpm, which can be relevant for running in the right zone, but it seems usually to catch up.

0 Former Member over 9 years ago

At present I'm at 70% battery about 43 hours and one 35 minute GPS run since coming off the charger at 100%. Everything on.

I have not found that bluetooth makes much difference and leave it and GC on all the time. I charge after 5 days when down to about 20% with everything on and about total 2-2.5 hours of GPS included activity with 1 sec sampling. The trend is pretty predictable and the charge time is pretty fast so I do not get surprises of running out. I wish my phone was like that.

0 philippe.berini over 9 years ago

Here's another graph from my last run (see post above). This time I also added cadence. Since I've done it in Excel and all data uses the same axis, it's very easy to identify cadence lock.

It was only once and only for a very short period of time, the FR235 caught up pretty quickly (after one minute). This probably happend when I went downhill for a short period. Cadence stayed the same but the true HR (measured with the tickrx chest strap) went down, while the FR235 HR tagged along the cadence.

0 dhiltonp over 9 years ago

Thanks, Phillipe - it's cool to see that little lock period.

0 philippe.berini over 9 years ago

Thanks, Phillipe - it's cool to see that little lock period.

It would be even cooler not to see that at all ;)

Now that I look at the picture again, there might be a slight hint of another crossover, just right from the circle. There HR crossed over cadence on upwards direction and it looks like the F235 struggled just a bit as well, even though it doesn't look as "clear" as the other one.

A double-crossover :rolleyes:

0 Former Member over 9 years ago

It would be even cooler not to see that at all ;)

Now that I look at the picture again, there might be a slight hint of another crossover, just right from the circle. There HR crossed over cadence on upwards direction and it looks like the F235 struggled just a bit as well, even though it doesn't look as "clear" as the other one.

A double-crossover :rolleyes:

What are you using to make those graphs?

0 philippe.berini over 9 years ago

What are you using to make those graphs?

Short answer: mygpsfiles and later Excel.

Long answer:

When comparing the FR235 to my H7 chest strap, I mostly used mygpsfiles.com to create the graphs. However this only works if the tcx file contains a valid gps track. I.e. you can't compare an indoor run with that service.

Later I used a wahoo Tickr X chest strap which can record HR data without any other device, but of course without gps, so mygpsfiles doesn't work for that. I exported the Tickr X training to Garmin connect. From there I exported both trainings (once recorded with the FR235 and the other with the Tickr X) as TCX files.

Those I opened in Excel as XML table. Luckily they had the same timestamps so it was easy to make a VLOOKUP to compare the data. However there could be a slight lag, since I don't know how well synchronized time in the Tickr X compared to my FR235 is.

0 Former Member over 9 years ago

My graphic comparison between Forerunner 220 and Forerunner 235 in the same activity. It is specially slow when starting the activity.

0 philippe.berini over 9 years ago

Finally my cold is mostly gone and I could head out again...

Here's todays run with FW 3.25beta and WHR 2.40.

The tickr x starts earlier and ends later because it is automatically recording once it's on the chest. The FR235 was tracking nicely for most of the time. It was a steady run with a few hills, therefore some up and downs in HR. Versus the end I met an old friend from school, so I was having a chat. Interestingly the FR235 suddenly spiked up before I was running again.

The cadence I found in the TCX from the FR235 Export seems completly wrong. It's from the column "runCadence" but it is very different from what I see in Garmin Connect. I suppose there might be an export issue here.

0 timgrose over 9 years ago

Cadence looks like the "old style" full cycle 0-100 type values - i.e. half the single foot ones now in use.

The FIT file actually stores cadence in two fields - the full cycle field then a fractional 0 or 0.5 value. So the programs needs to add these together and then double the result.

TCX I think outputs the full cycle values as it is quite an old protocol. Garmin started doing the single step values when the 620 came out and the HRM-Run could record odd or even values.